diff --git a/src/main/scala/gitbucket/core/service/PullRequestService.scala b/src/main/scala/gitbucket/core/service/PullRequestService.scala
index 0f7f50c..c6cde8e 100644
--- a/src/main/scala/gitbucket/core/service/PullRequestService.scala
+++ b/src/main/scala/gitbucket/core/service/PullRequestService.scala
@@ -116,6 +116,24 @@
       .map { case (t1, t2) => t1 }
       .list
 
+  def getPullRequestsByBranch(userName: String, repositoryName: String, branch: String, closed: Option[Boolean])(
+    implicit s: Session
+  ): List[PullRequest] =
+    PullRequests
+      .join(Issues)
+      .on { (t1, t2) =>
+        t1.byPrimaryKey(t2.userName, t2.repositoryName, t2.issueId)
+      }
+      .filter {
+        case (t1, t2) =>
+          (t1.requestUserName === userName.bind) &&
+            (t1.requestRepositoryName === repositoryName.bind) &&
+            (t1.branch === branch.bind) &&
+            (t2.closed === closed.get.bind, closed.isDefined)
+      }
+      .map { case (t1, t2) => t1 }
+      .list
+
   /**
    * for repository viewer.
    * 1. find pull request from `branch` to other branch on same repository
@@ -358,6 +376,14 @@
       .sortWith(_.registeredDate before _.registeredDate)
   }
 
+  def markMergeAndClosePullRequest(userName: String, owner: String, repository: String, pull: PullRequest)(
+    implicit s: Session
+  ): Unit = {
+    createComment(owner, repository, userName, pull.issueId, "Merged by user", "merge")
+    createComment(owner, repository, userName, pull.issueId, "Close", "close")
+    updateClosed(owner, repository, pull.issueId, true)
+  }
+
 }
 
 object PullRequestService {
diff --git a/src/main/scala/gitbucket/core/servlet/GitRepositoryServlet.scala b/src/main/scala/gitbucket/core/servlet/GitRepositoryServlet.scala
index 0a8d956..3ae5257 100644
--- a/src/main/scala/gitbucket/core/servlet/GitRepositoryServlet.scala
+++ b/src/main/scala/gitbucket/core/servlet/GitRepositoryServlet.scala
@@ -303,6 +303,19 @@
               } else None
             }
 
+            // set PR as merged
+            val pulls = getPullRequestsByBranch(owner, repository, branchName, Some(false))
+            pulls.foreach { pull =>
+              if (commits.find { c =>
+                    c.id == pull.commitIdTo
+                  }.isDefined) {
+                markMergeAndClosePullRequest(pusher, owner, repository, pull)
+                getAccountByUserName(pusher).map { pusherAccount =>
+                  callPullRequestWebHook("closed", repositoryInfo, pull.issueId, baseUrl, pusherAccount)
+                }
+              }
+            }
+
             // record activity
             if (refName(1) == "heads") {
               command.getType match {