diff --git a/routers/api/v1/repo/repo.go b/routers/api/v1/repo/repo.go
index ae9378ac9..0d129e278 100644
--- a/routers/api/v1/repo/repo.go
+++ b/routers/api/v1/repo/repo.go
@@ -895,9 +895,12 @@ func CompareDiff(ctx *context.APIContext) {
 		Diff      interface{}
 		LatestSha string
 	}{
-		Commits:   result,
-		Diff:      ctx.Context.Data["Diff"],
-		LatestSha: headBranch,
+		Commits: result,
+		Diff:    ctx.Context.Data["Diff"],
+	}
+
+	if len(different.Commits) != 0 {
+		different.LatestSha = different.Commits[0].Sha
 	}
 
 	ctx.JSON(200, different)