diff --git a/services/tech/tech.go b/services/tech/tech.go
index 9217ac918e..3bed459191 100644
--- a/services/tech/tech.go
+++ b/services/tech/tech.go
@@ -120,12 +120,16 @@ func SearchRepoInfoWithInstitution(opt *models.SearchRepoOpt) ([]*models.RepoWit
 		return []*models.RepoWithInstitution{}, 0, nil
 	}
 	repoIds, institutionMap := getRepoIdAndInstitutionMap(infos)
+	topics := make([]string, 0)
+	if opt.Topic != "" {
+		topics = append(topics, opt.Topic)
+	}
 
 	result, err := repository.FindRepos(repository.FindReposOptions{
 		ListOptions: models.ListOptions{Page: opt.Page, PageSize: opt.PageSize},
 		Sort:        opt.OrderBy,
 		Keyword:     opt.Q,
-		Topics:      []string{opt.Topic},
+		Topics:      topics,
 		RepoIds:     repoIds,
 	})