diff --git a/src/main/scala/gitbucket/core/controller/IssuesController.scala b/src/main/scala/gitbucket/core/controller/IssuesController.scala
index 1aafbeb..cd3edc3 100644
--- a/src/main/scala/gitbucket/core/controller/IssuesController.scala
+++ b/src/main/scala/gitbucket/core/controller/IssuesController.scala
@@ -348,9 +348,12 @@
 
   private def createReferComment(owner: String, repository: String, fromIssue: Issue, message: String) = {
     StringUtil.extractIssueId(message).foreach { issueId =>
+      val content = fromIssue.issueId + ":" + fromIssue.title
       if(getIssue(owner, repository, issueId).isDefined){
-        createComment(owner, repository, context.loginAccount.get.userName, issueId.toInt,
-                      fromIssue.issueId + ":" + fromIssue.title, "refer")
+        // Not add if refer comment already exist.
+        if(!getComments(owner, repository, issueId.toInt).exists { x => x.action == "refer" && x.content == content }) {
+          createComment(owner, repository, context.loginAccount.get.userName, issueId.toInt, content, "refer")
+        }
       }
     }
   }