diff --git a/ports/quectel/core/gnss.py b/ports/quectel/core/gnss.py
index cdc812ac9ff25e8846d7ca4315d840f5229bf460..dff9110201437a39b1e15aeb5fa9fd8a7f12a641 100644
--- a/ports/quectel/core/gnss.py
+++ b/ports/quectel/core/gnss.py
@@ -38,17 +38,23 @@ class GnssGetData:
     #读取GNSS数据并加以解析
     def read_gnss_data(self):
         try:
-            buf = self.uart.read(self.uart.any())
-            gps_data = buf.decode().strip("b")
-            self.r = ure.search("GNGGA(.+?)M", gps_data)
-            self.r1 = ure.search("GNRMC(.+?)M", gps_data)
-            self.r2 = ure.search("GPGSV(.+?)M", gps_data)
-            self.r3 = ure.search("GNVTG(.+?)M", gps_data)
-            global fixFlag
-            if self.r1.group(0).split(",")[2] == 'A': #有效定位
-                fixFlag=1
-            else:
-                fixFlag=0
+            msgLen = self.uart.any()
+            if msgLen:
+                buf = self.uart.read(self.uart.any())
+                gps_data = buf.decode().strip("b")
+                self.r = ure.search("GNGGA(.+?)M", gps_data)
+                self.r1 = ure.search("GNRMC(.+?)M", gps_data)
+                self.r2 = ure.search("GPGSV(.+?)M", gps_data)
+                self.r3 = ure.search("GNVTG(.+?)M", gps_data)
+                global fixFlag
+                if self.r1.group(0).split(",")[2] == 'A': #有效定位
+                    fixFlag=1
+                else:
+                    fixFlag=0
+
+                return True
+            else：
+                return False
         except:
             print("Exception:read gnss data error!!!!!!!!")
             raise