diff --git a/routers/web/repo/pull.go b/routers/web/repo/pull.go
index a9507332f8..c9a2bb4e08 100644
--- a/routers/web/repo/pull.go
+++ b/routers/web/repo/pull.go
@@ -638,7 +638,7 @@ func PrepareViewPullInfo(ctx *context.Context, issue *issues_model.Issue) *git.C
 		if pull.Flow == issues_model.PullRequestFlowGithub {
 			headBranchExist = headGitRepo.IsBranchExist(pull.HeadBranch)
 		} else {
-			headBranchExist = headGitRepo.IsReferenceExist(pull.GetGitRefName())
+			headBranchExist = baseGitRepo.IsReferenceExist(pull.GetGitRefName())
 		}
 
 		if headBranchExist {
diff --git a/services/automerge/automerge.go b/services/automerge/automerge.go
index 96a0e0498d..0cdc113379 100644
--- a/services/automerge/automerge.go
+++ b/services/automerge/automerge.go
@@ -162,7 +162,7 @@ func handlePullRequestAutoMerge(pullID int64, sha string) {
 			return
 		}
 	case issues_model.PullRequestFlowAGit:
-		headBranchExist := headGitRepo.IsReferenceExist(pr.GetGitRefName())
+		headBranchExist := baseGitRepo.IsReferenceExist(pr.GetGitRefName())
 		if !headBranchExist {
 			log.Warn("Head branch of auto merge %-v does not exist [HeadRepoID: %d, Branch(Agit): %s]", pr, pr.HeadRepoID, pr.HeadBranch)
 			return