diff --git a/models/repo/release.go b/models/repo/release.go
index 663d310bc027d..b4637665ab6f7 100644
--- a/models/repo/release.go
+++ b/models/repo/release.go
@@ -161,6 +161,11 @@ func UpdateRelease(ctx context.Context, rel *Release) error {
 	return err
 }
 
+func UpdateReleaseNumCommits(ctx context.Context, rel *Release) error {
+	_, err := db.GetEngine(ctx).ID(rel.ID).Cols("num_commits").Update(rel)
+	return err
+}
+
 // AddReleaseAttachments adds a release attachments
 func AddReleaseAttachments(ctx context.Context, releaseID int64, attachmentUUIDs []string) (err error) {
 	// Check attachments
diff --git a/services/context/repo.go b/services/context/repo.go
index 6f5c772f5e994..64f929829f066 100644
--- a/services/context/repo.go
+++ b/services/context/repo.go
@@ -920,17 +920,40 @@ func RepoRefByType(detectRefType git.RefType) func(*Context) {
 		ctx.Data["RefFullName"] = ctx.Repo.RefFullName
 		ctx.Data["RefTypeNameSubURL"] = ctx.Repo.RefTypeNameSubURL()
 		ctx.Data["TreePath"] = ctx.Repo.TreePath
-
 		ctx.Data["BranchName"] = ctx.Repo.BranchName
-
 		ctx.Data["CommitID"] = ctx.Repo.CommitID
-
 		ctx.Data["CanCreateBranch"] = ctx.Repo.CanCreateBranch() // only used by the branch selector dropdown: AllowCreateNewRef
 
-		ctx.Repo.CommitsCount, err = ctx.Repo.GetCommitsCount()
-		if err != nil {
-			ctx.ServerError("GetCommitsCount", err)
-			return
+		// if it's a tag, we just get the commits count from database
+		if ctx.Repo.RefFullName.IsTag() {
+			rel, err := repo_model.GetRelease(ctx, ctx.Repo.Repository.ID, ctx.Repo.RefFullName.TagName())
+			if err != nil {
+				if repo_model.IsErrReleaseNotExist(err) {
+					ctx.NotFound(err)
+					return
+				}
+				ctx.ServerError("GetRelease", err)
+				return
+			}
+			// for mirror tags, the number of commist may not be set
+			if rel.NumCommits <= 0 {
+				rel.NumCommits, err = ctx.Repo.GetCommitsCount()
+				if err != nil {
+					ctx.ServerError("GetCommitsCount", err)
+					return
+				}
+				if err := repo_model.UpdateReleaseNumCommits(ctx, rel); err != nil {
+					ctx.ServerError("UpdateReleaseNumCommits", err)
+					return
+				}
+			}
+			ctx.Repo.CommitsCount = rel.NumCommits
+		} else {
+			ctx.Repo.CommitsCount, err = ctx.Repo.GetCommitsCount()
+			if err != nil {
+				ctx.ServerError("GetCommitsCount", err)
+				return
+			}
 		}
 		ctx.Data["CommitsCount"] = ctx.Repo.CommitsCount
 		ctx.Repo.GitRepo.LastCommitCache = git.NewLastCommitCache(ctx.Repo.CommitsCount, ctx.Repo.Repository.FullName(), ctx.Repo.GitRepo, cache.GetCache())