diff --git a/include/report_json_file.h b/include/report_json_file.h
index a46bf9789891e1a20aac8d20ed59f447ce02a815..ed2ab8d86f456a79f94e001137c01b8c686fa623 100755
--- a/include/report_json_file.h
+++ b/include/report_json_file.h
@@ -137,7 +137,6 @@ void OutputJsonMapList(FILE *output, const std::string &key, const std::map<K, V
         }
     }
     if (fprintf(output, "\"%s\":[", key.c_str()) != -1) {
-        fprintf(output, "[");
         auto it = value.begin();
         while (it != value.end()) {
             OutputJsonValue(output, it->second, it == value.begin());