diff --git a/routers/api/v1/repo/pull.go b/routers/api/v1/repo/pull.go
index a0117794ad54..9fbadcd07668 100644
--- a/routers/api/v1/repo/pull.go
+++ b/routers/api/v1/repo/pull.go
@@ -405,7 +405,7 @@ func EditPullRequest(ctx *context.APIContext, form api.EditPullRequestOption) {
 		}
 	}
 
-	if ctx.Repo.CanWrite(models.UnitTypePullRequests) && (form.Labels != nil && len(form.Labels) > 0) {
+	if ctx.Repo.CanWrite(models.UnitTypePullRequests) && form.Labels != nil {
 		labels, err := models.GetLabelsInRepoByIDs(ctx.Repo.Repository.ID, form.Labels)
 		if err != nil {
 			ctx.Error(500, "GetLabelsInRepoByIDsError", err)