diff --git a/models/fixtures/mirror.yml b/models/fixtures/mirror.yml
new file mode 100644
index 0000000000..97bc4ae60d
--- /dev/null
+++ b/models/fixtures/mirror.yml
@@ -0,0 +1,49 @@
+-
+  id: 1
+  repo_id: 5
+  interval: 3600
+  enable_prune: false
+  updated_unix: 0
+  next_update_unix: 0
+  lfs_enabled: false
+  lfs_endpoint: ""
+
+-
+  id: 2
+  repo_id: 25
+  interval: 3600
+  enable_prune: false
+  updated_unix: 0
+  next_update_unix: 0
+  lfs_enabled: false
+  lfs_endpoint: ""
+
+-
+  id: 3
+  repo_id: 26
+  interval: 3600
+  enable_prune: false
+  updated_unix: 0
+  next_update_unix: 0
+  lfs_enabled: false
+  lfs_endpoint: ""
+
+-
+  id: 4
+  repo_id: 27
+  interval: 3600
+  enable_prune: false
+  updated_unix: 0
+  next_update_unix: 0
+  lfs_enabled: false
+  lfs_endpoint: ""
+
+-
+  id: 5
+  repo_id: 28
+  interval: 3600
+  enable_prune: false
+  updated_unix: 0
+  next_update_unix: 0
+  lfs_enabled: false
+  lfs_endpoint: ""
diff --git a/models/fixtures/repository.yml b/models/fixtures/repository.yml
index ef7730780f..050a9e2d06 100644
--- a/models/fixtures/repository.yml
+++ b/models/fixtures/repository.yml
@@ -141,7 +141,7 @@
   num_projects: 0
   num_closed_projects: 0
   is_private: true
-  is_empty: true
+  is_empty: false
   is_archived: false
   is_mirror: true
   status: 0
diff --git a/routers/api/v1/repo/branch.go b/routers/api/v1/repo/branch.go
index 4900ecf4d0..5e2c9878f0 100644
--- a/routers/api/v1/repo/branch.go
+++ b/routers/api/v1/repo/branch.go
@@ -118,6 +118,21 @@ func DeleteBranch(ctx *context.APIContext) {
 	//   "404":
 	//     "$ref": "#/responses/notFound"
 
+	if ctx.Repo.Repository.IsEmpty {
+		ctx.Error(http.StatusNotFound, "", "Git Repository is empty.")
+		return
+	}
+
+	if ctx.Repo.Repository.IsArchived {
+		ctx.Error(http.StatusForbidden, "", "Git Repository is archived.")
+		return
+	}
+
+	if ctx.Repo.Repository.IsMirror {
+		ctx.Error(http.StatusForbidden, "", "Git Repository is a mirror.")
+		return
+	}
+
 	branchName := ctx.Params("*")
 
 	if ctx.Repo.Repository.IsEmpty {
@@ -195,17 +210,30 @@ func CreateBranch(ctx *context.APIContext) {
 	// responses:
 	//   "201":
 	//     "$ref": "#/responses/Branch"
+	//   "403":
+	//     description: The branch is archived or a mirror.
 	//   "404":
 	//     description: The old branch does not exist.
 	//   "409":
 	//     description: The branch with the same name already exists.
 
-	opt := web.GetForm(ctx).(*api.CreateBranchRepoOption)
 	if ctx.Repo.Repository.IsEmpty {
 		ctx.Error(http.StatusNotFound, "", "Git Repository is empty.")
 		return
 	}
 
+	if ctx.Repo.Repository.IsArchived {
+		ctx.Error(http.StatusForbidden, "", "Git Repository is archived.")
+		return
+	}
+
+	if ctx.Repo.Repository.IsMirror {
+		ctx.Error(http.StatusForbidden, "", "Git Repository is a mirror.")
+		return
+	}
+
+	opt := web.GetForm(ctx).(*api.CreateBranchRepoOption)
+
 	var oldCommit *git.Commit
 	var err error
 
@@ -313,7 +341,12 @@ func ListBranches(ctx *context.APIContext) {
 
 	listOptions := utils.GetListOptions(ctx)
 
-	if !ctx.Repo.Repository.IsEmpty && ctx.Repo.GitRepo != nil {
+	if !ctx.Repo.Repository.IsEmpty {
+		if ctx.Repo.GitRepo == nil {
+			ctx.Error(http.StatusInternalServerError, "Load git repository failed", nil)
+			return
+		}
+
 		branchOpts := git_model.FindBranchOptions{
 			ListOptions:     listOptions,
 			RepoID:          ctx.Repo.Repository.ID,
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
index f98dc12d95..4c6ee55f84 100644
--- a/templates/swagger/v1_json.tmpl
+++ b/templates/swagger/v1_json.tmpl
@@ -3606,6 +3606,9 @@
           "201": {
             "$ref": "#/responses/Branch"
           },
+          "403": {
+            "description": "The branch is archived or a mirror."
+          },
           "404": {
             "description": "The old branch does not exist."
           },
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/HEAD b/tests/gitea-repositories-meta/user3/repo5.git/HEAD
new file mode 100644
index 0000000000..cb089cd89a
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/HEAD
@@ -0,0 +1 @@
+ref: refs/heads/master
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/config b/tests/gitea-repositories-meta/user3/repo5.git/config
new file mode 100644
index 0000000000..e6da231579
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/config
@@ -0,0 +1,6 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+	ignorecase = true
+	precomposeunicode = true
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/description b/tests/gitea-repositories-meta/user3/repo5.git/description
new file mode 100644
index 0000000000..498b267a8c
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/description
@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/hooks/post-receive b/tests/gitea-repositories-meta/user3/repo5.git/hooks/post-receive
new file mode 100755
index 0000000000..4b3d452abc
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/hooks/post-receive
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+ORI_DIR=`pwd`
+SHELL_FOLDER=$(cd "$(dirname "$0")";pwd)
+cd "$ORI_DIR"
+for i in `ls "$SHELL_FOLDER/post-receive.d"`; do
+    sh "$SHELL_FOLDER/post-receive.d/$i"
+done
\ No newline at end of file
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/hooks/post-receive.d/gitea b/tests/gitea-repositories-meta/user3/repo5.git/hooks/post-receive.d/gitea
new file mode 100755
index 0000000000..43a948da3a
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/hooks/post-receive.d/gitea
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+"$GITEA_ROOT/gitea" hook --config="$GITEA_ROOT/$GITEA_CONF" post-receive
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/hooks/pre-receive b/tests/gitea-repositories-meta/user3/repo5.git/hooks/pre-receive
new file mode 100755
index 0000000000..4127013053
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/hooks/pre-receive
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+ORI_DIR=`pwd`
+SHELL_FOLDER=$(cd "$(dirname "$0")";pwd)
+cd "$ORI_DIR"
+for i in `ls "$SHELL_FOLDER/pre-receive.d"`; do
+    sh "$SHELL_FOLDER/pre-receive.d/$i"
+done
\ No newline at end of file
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/hooks/pre-receive.d/gitea b/tests/gitea-repositories-meta/user3/repo5.git/hooks/pre-receive.d/gitea
new file mode 100755
index 0000000000..49d0940636
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/hooks/pre-receive.d/gitea
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+"$GITEA_ROOT/gitea" hook --config="$GITEA_ROOT/$GITEA_CONF" pre-receive
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/hooks/update b/tests/gitea-repositories-meta/user3/repo5.git/hooks/update
new file mode 100755
index 0000000000..c186fe4a18
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/hooks/update
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+ORI_DIR=`pwd`
+SHELL_FOLDER=$(cd "$(dirname "$0")";pwd)
+cd "$ORI_DIR"
+for i in `ls "$SHELL_FOLDER/update.d"`; do
+    sh "$SHELL_FOLDER/update.d/$i" $1 $2 $3
+done
\ No newline at end of file
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/hooks/update.d/gitea b/tests/gitea-repositories-meta/user3/repo5.git/hooks/update.d/gitea
new file mode 100755
index 0000000000..38101c2426
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/hooks/update.d/gitea
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+"$GITEA_ROOT/gitea" hook --config="$GITEA_ROOT/$GITEA_CONF" update $1 $2 $3
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/info/exclude b/tests/gitea-repositories-meta/user3/repo5.git/info/exclude
new file mode 100644
index 0000000000..a5196d1be8
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/info/exclude
@@ -0,0 +1,6 @@
+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/20/ade30d25e0ecaeec84e7f542a8456900858240 b/tests/gitea-repositories-meta/user3/repo5.git/objects/20/ade30d25e0ecaeec84e7f542a8456900858240
new file mode 100644
index 0000000000..9f3ffe5f27
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/20/ade30d25e0ecaeec84e7f542a8456900858240 differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/27/74debeea6dc742cc4971a92db0e08b95b60588 b/tests/gitea-repositories-meta/user3/repo5.git/objects/27/74debeea6dc742cc4971a92db0e08b95b60588
new file mode 100644
index 0000000000..5d9226f7a1
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/27/74debeea6dc742cc4971a92db0e08b95b60588 differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/2a/47ca4b614a9f5a43abbd5ad851a54a616ffee6 b/tests/gitea-repositories-meta/user3/repo5.git/objects/2a/47ca4b614a9f5a43abbd5ad851a54a616ffee6
new file mode 100644
index 0000000000..ca60d2314f
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/2a/47ca4b614a9f5a43abbd5ad851a54a616ffee6 differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/2f/9b22fd3159a43b7b4e5dd806fcd544edf8716f b/tests/gitea-repositories-meta/user3/repo5.git/objects/2f/9b22fd3159a43b7b4e5dd806fcd544edf8716f
new file mode 100644
index 0000000000..e98d752dad
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/2f/9b22fd3159a43b7b4e5dd806fcd544edf8716f differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/d2/2b4d4daa5be07329fcef6ed458f00cf3392da0 b/tests/gitea-repositories-meta/user3/repo5.git/objects/d2/2b4d4daa5be07329fcef6ed458f00cf3392da0
new file mode 100644
index 0000000000..e319f8ce34
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/d2/2b4d4daa5be07329fcef6ed458f00cf3392da0 differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/d5/6a3073c1dbb7b15963110a049d50cdb5db99fc b/tests/gitea-repositories-meta/user3/repo5.git/objects/d5/6a3073c1dbb7b15963110a049d50cdb5db99fc
new file mode 100644
index 0000000000..eff3c9833e
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/d5/6a3073c1dbb7b15963110a049d50cdb5db99fc differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/ec/f0db3c1ec806522de4b491fb9a3c7457398c61 b/tests/gitea-repositories-meta/user3/repo5.git/objects/ec/f0db3c1ec806522de4b491fb9a3c7457398c61
new file mode 100644
index 0000000000..ed431f70d3
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/ec/f0db3c1ec806522de4b491fb9a3c7457398c61 differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/objects/ee/16d127df463aa491e08958120f2108b02468df b/tests/gitea-repositories-meta/user3/repo5.git/objects/ee/16d127df463aa491e08958120f2108b02468df
new file mode 100644
index 0000000000..e177f69e37
Binary files /dev/null and b/tests/gitea-repositories-meta/user3/repo5.git/objects/ee/16d127df463aa491e08958120f2108b02468df differ
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/refs/heads/master b/tests/gitea-repositories-meta/user3/repo5.git/refs/heads/master
new file mode 100644
index 0000000000..ccee722d52
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/refs/heads/master
@@ -0,0 +1 @@
+2a47ca4b614a9f5a43abbd5ad851a54a616ffee6
diff --git a/tests/gitea-repositories-meta/user3/repo5.git/refs/heads/test_branch b/tests/gitea-repositories-meta/user3/repo5.git/refs/heads/test_branch
new file mode 100644
index 0000000000..dfe0c6a128
--- /dev/null
+++ b/tests/gitea-repositories-meta/user3/repo5.git/refs/heads/test_branch
@@ -0,0 +1 @@
+d22b4d4daa5be07329fcef6ed458f00cf3392da0
diff --git a/tests/integration/api_repo_branch_test.go b/tests/integration/api_repo_branch_test.go
new file mode 100644
index 0000000000..3065a92d69
--- /dev/null
+++ b/tests/integration/api_repo_branch_test.go
@@ -0,0 +1,126 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"testing"
+
+	auth_model "code.gitea.io/gitea/models/auth"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/setting"
+	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAPIRepoBranchesPlain(t *testing.T) {
+	onGiteaRun(t, func(*testing.T, *url.URL) {
+		repo3 := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 3})
+		user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+		session := loginUser(t, user1.LowerName)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+
+		link, _ := url.Parse(fmt.Sprintf("/api/v1/repos/user3/%s/branches", repo3.Name)) // a plain repo
+		link.RawQuery = url.Values{"token": {token}}.Encode()
+		resp := MakeRequest(t, NewRequest(t, "GET", link.String()), http.StatusOK)
+		bs, err := io.ReadAll(resp.Body)
+		assert.NoError(t, err)
+
+		var branches []*api.Branch
+		assert.NoError(t, json.Unmarshal(bs, &branches))
+		assert.Len(t, branches, 2)
+		assert.EqualValues(t, "test_branch", branches[0].Name)
+		assert.EqualValues(t, "master", branches[1].Name)
+
+		link2, _ := url.Parse(fmt.Sprintf("/api/v1/repos/user3/%s/branches/test_branch", repo3.Name))
+		link2.RawQuery = url.Values{"token": {token}}.Encode()
+		resp = MakeRequest(t, NewRequest(t, "GET", link2.String()), http.StatusOK)
+		bs, err = io.ReadAll(resp.Body)
+		assert.NoError(t, err)
+		var branch api.Branch
+		assert.NoError(t, json.Unmarshal(bs, &branch))
+		assert.EqualValues(t, "test_branch", branch.Name)
+
+		req := NewRequest(t, "POST", link.String())
+		req.Header.Add("Content-Type", "application/json")
+		req.Body = io.NopCloser(bytes.NewBufferString(`{"new_branch_name":"test_branch2", "old_branch_name": "test_branch", "old_ref_name":"refs/heads/test_branch"}`))
+		resp = MakeRequest(t, req, http.StatusCreated)
+		bs, err = io.ReadAll(resp.Body)
+		assert.NoError(t, err)
+		var branch2 api.Branch
+		assert.NoError(t, json.Unmarshal(bs, &branch2))
+		assert.EqualValues(t, "test_branch2", branch2.Name)
+		assert.EqualValues(t, branch.Commit.ID, branch2.Commit.ID)
+
+		resp = MakeRequest(t, NewRequest(t, "GET", link.String()), http.StatusOK)
+		bs, err = io.ReadAll(resp.Body)
+		assert.NoError(t, err)
+
+		branches = []*api.Branch{}
+		assert.NoError(t, json.Unmarshal(bs, &branches))
+		assert.Len(t, branches, 3)
+		assert.EqualValues(t, "test_branch", branches[0].Name)
+		assert.EqualValues(t, "test_branch2", branches[1].Name)
+		assert.EqualValues(t, "master", branches[2].Name)
+
+		link3, _ := url.Parse(fmt.Sprintf("/api/v1/repos/user3/%s/branches/test_branch2", repo3.Name))
+		MakeRequest(t, NewRequest(t, "DELETE", link3.String()), http.StatusNotFound)
+
+		link3.RawQuery = url.Values{"token": {token}}.Encode()
+		MakeRequest(t, NewRequest(t, "DELETE", link3.String()), http.StatusNoContent)
+		assert.NoError(t, err)
+	})
+}
+
+func TestAPIRepoBranchesMirror(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	repo5 := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 5})
+	user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	session := loginUser(t, user1.LowerName)
+	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+
+	link, _ := url.Parse(fmt.Sprintf("/api/v1/repos/user3/%s/branches", repo5.Name)) // a mirror repo
+	link.RawQuery = url.Values{"token": {token}}.Encode()
+	resp := MakeRequest(t, NewRequest(t, "GET", link.String()), http.StatusOK)
+	bs, err := io.ReadAll(resp.Body)
+	assert.NoError(t, err)
+
+	var branches []*api.Branch
+	assert.NoError(t, json.Unmarshal(bs, &branches))
+	assert.Len(t, branches, 2)
+	assert.EqualValues(t, "test_branch", branches[0].Name)
+	assert.EqualValues(t, "master", branches[1].Name)
+
+	link2, _ := url.Parse(fmt.Sprintf("/api/v1/repos/user3/%s/branches/test_branch", repo5.Name))
+	link2.RawQuery = url.Values{"token": {token}}.Encode()
+	resp = MakeRequest(t, NewRequest(t, "GET", link2.String()), http.StatusOK)
+	bs, err = io.ReadAll(resp.Body)
+	assert.NoError(t, err)
+	var branch api.Branch
+	assert.NoError(t, json.Unmarshal(bs, &branch))
+	assert.EqualValues(t, "test_branch", branch.Name)
+
+	req := NewRequest(t, "POST", link.String())
+	req.Header.Add("Content-Type", "application/json")
+	req.Body = io.NopCloser(bytes.NewBufferString(`{"new_branch_name":"test_branch2", "old_branch_name": "test_branch", "old_ref_name":"refs/heads/test_branch"}`))
+	resp = MakeRequest(t, req, http.StatusForbidden)
+	bs, err = io.ReadAll(resp.Body)
+	assert.NoError(t, err)
+	assert.EqualValues(t, "{\"message\":\"Git Repository is a mirror.\",\"url\":\""+setting.AppURL+"api/swagger\"}\n", string(bs))
+
+	resp = MakeRequest(t, NewRequest(t, "DELETE", link2.String()), http.StatusForbidden)
+	bs, err = io.ReadAll(resp.Body)
+	assert.NoError(t, err)
+	assert.EqualValues(t, "{\"message\":\"Git Repository is a mirror.\",\"url\":\""+setting.AppURL+"api/swagger\"}\n", string(bs))
+}
diff --git a/tests/integration/empty_repo_test.go b/tests/integration/empty_repo_test.go
index f0022f4db3..d604391dab 100644
--- a/tests/integration/empty_repo_test.go
+++ b/tests/integration/empty_repo_test.go
@@ -34,7 +34,7 @@ func TestEmptyRepo(t *testing.T) {
 		"commit/1ae57b34ccf7e18373",
 		"graph",
 	}
-	emptyRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 5})
+	emptyRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 6})
 	assert.True(t, emptyRepo.IsEmpty)
 	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: emptyRepo.OwnerID})
 	for _, subPath := range subPaths {