diff --git a/examples/modbus/rtu_master_err.py b/examples/modbus/rtu_master_err.py
new file mode 100644
index 000000000..d203e8645
--- /dev/null
+++ b/examples/modbus/rtu_master_err.py
@@ -0,0 +1,20 @@
+# Import modbus module
+import modbus
+
+# Create a ModBusRTU object, specify the send buffer and receive buffer size as 128 bytes
+mb = modbus.ModBusRTU(128, 128)
+
+# Set slave address to 1
+mb.setSlave(1)
+
+# Generate a request frame for reading registers, specify the start address as 0 and the quantity as 10
+send_buff = mb.serializeReadRegisters(0, 10)
+
+# Print the byte string of the request frame
+print(send_buff)
+
+# Parse a response frame for reading registers, return a list containing the values of the registers
+host_regists = mb.deserializeReadRegisters(
+    b'\x01\x03\x14\x00\x00\x04\xD2\x00\x00\x00\x00\x00\x7B\x00\x00\x00\x00\x00\x00\x00\x00\xE5\x0B'
+)
+print(host_regists)
diff --git a/package/modbus/modbus.py b/package/modbus/modbus.py
index 891757084..aa17edbe7 100644
--- a/package/modbus/modbus.py
+++ b/package/modbus/modbus.py
@@ -151,6 +151,8 @@ class ModBus(_modbus._ModBus):
         """
         self.readBuff = msg
         dest = super().deserializeReadRegisters(len(msg))
+        if dest is None:
+            return None
         ret = []
         for i in range(0, len(dest), 2):
             ret.append(int(dest[i]) + int(dest[i + 1]) * 256)
@@ -168,6 +170,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeReadBits(length)
+        if dest is None:
+            return None
         return list(dest)
 
     def deserializeReadInputBits(self, msg: bytes) -> list:
@@ -182,6 +186,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeReadInputBits(length)
+        if dest is None:
+            return None
         return list(dest)
 
     def deserializeReadInputRegisters(self, msg: bytes) -> list:
@@ -196,6 +202,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeReadInputRegisters(length)
+        if dest is None:
+            return None
         ret = []
         for i in range(0, len(dest), 2):
             ret.append(int(dest[i]) + int(dest[i + 1]) * 256)
@@ -213,6 +221,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeWriteAndReadRegisters(length)
+        if dest is None:
+            return None
         ret = []
         for i in range(0, len(dest), 2):
             ret.append(int(dest[i]) + int(dest[i + 1]) * 256)
diff --git a/port/linux/package/pikascript/modbus.py b/port/linux/package/pikascript/modbus.py
index 891757084..aa17edbe7 100644
--- a/port/linux/package/pikascript/modbus.py
+++ b/port/linux/package/pikascript/modbus.py
@@ -151,6 +151,8 @@ class ModBus(_modbus._ModBus):
         """
         self.readBuff = msg
         dest = super().deserializeReadRegisters(len(msg))
+        if dest is None:
+            return None
         ret = []
         for i in range(0, len(dest), 2):
             ret.append(int(dest[i]) + int(dest[i + 1]) * 256)
@@ -168,6 +170,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeReadBits(length)
+        if dest is None:
+            return None
         return list(dest)
 
     def deserializeReadInputBits(self, msg: bytes) -> list:
@@ -182,6 +186,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeReadInputBits(length)
+        if dest is None:
+            return None
         return list(dest)
 
     def deserializeReadInputRegisters(self, msg: bytes) -> list:
@@ -196,6 +202,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeReadInputRegisters(length)
+        if dest is None:
+            return None
         ret = []
         for i in range(0, len(dest), 2):
             ret.append(int(dest[i]) + int(dest[i + 1]) * 256)
@@ -213,6 +221,8 @@ class ModBus(_modbus._ModBus):
         self.readBuff = msg
         length = len(msg)
         dest = super().deserializeWriteAndReadRegisters(length)
+        if dest is None:
+            return None
         ret = []
         for i in range(0, len(dest), 2):
             ret.append(int(dest[i]) + int(dest[i + 1]) * 256)
diff --git a/test/module-test.cpp b/test/module-test.cpp
index 1b273ffa9..fa9765831 100644
--- a/test/module-test.cpp
+++ b/test/module-test.cpp
@@ -591,6 +591,9 @@ TEST(module, REPL_stdtask) {
     obj_deinit(pikaMain);
     EXPECT_EQ(pikaMemNow(), 0);
 }
+
+TEST_SINGLE_FILE(modbus, rtu_master_err, "test/python/modbus/rtu_master_err.py")
+
 #endif
 
 TEST_END
\ No newline at end of file
diff --git a/test/python/modbus/rtu_master_err.py b/test/python/modbus/rtu_master_err.py
new file mode 100644
index 000000000..d203e8645
--- /dev/null
+++ b/test/python/modbus/rtu_master_err.py
@@ -0,0 +1,20 @@
+# Import modbus module
+import modbus
+
+# Create a ModBusRTU object, specify the send buffer and receive buffer size as 128 bytes
+mb = modbus.ModBusRTU(128, 128)
+
+# Set slave address to 1
+mb.setSlave(1)
+
+# Generate a request frame for reading registers, specify the start address as 0 and the quantity as 10
+send_buff = mb.serializeReadRegisters(0, 10)
+
+# Print the byte string of the request frame
+print(send_buff)
+
+# Parse a response frame for reading registers, return a list containing the values of the registers
+host_regists = mb.deserializeReadRegisters(
+    b'\x01\x03\x14\x00\x00\x04\xD2\x00\x00\x00\x00\x00\x7B\x00\x00\x00\x00\x00\x00\x00\x00\xE5\x0B'
+)
+print(host_regists)