diff --git a/src/serial_AT.cpp b/src/serial_AT.cpp
index d2f164b..f050341 100644
--- a/src/serial_AT.cpp
+++ b/src/serial_AT.cpp
@@ -321,7 +321,7 @@ static void handle_serial_at_data(const std::string& data)
         // =======================
         // QENG="servingcell" 解析
         // =======================
-        if (line.find("+QENG:") == 0)
+        if (line.rfind("+QENG:", 0) == 0)
         {
             parse_qeng_servingcell(line);
             continue;