diff --git a/APP_Framework/Framework/control/ipc_protocol/modbus_uart/modbus_uart.c b/APP_Framework/Framework/control/ipc_protocol/modbus_uart/modbus_uart.c
index ef5f0351c..bd86ecf0c 100644
--- a/APP_Framework/Framework/control/ipc_protocol/modbus_uart/modbus_uart.c
+++ b/APP_Framework/Framework/control/ipc_protocol/modbus_uart/modbus_uart.c
@@ -107,16 +107,28 @@ static int ModbusUartTransformRecvBuffToData(ModbusUartReadItem *p_read_item, ui
  */
 static int ModbusUartGetDataBySerial(ModbusUartReadItem *p_read_item)
 {
-    uint32_t read_length = 0;
+    uint32_t cmd_length, read_length = 0;
     memset(recv_buff, 0, sizeof(recv_buff));
 
     ModbusUartDataInfo *p_modbus_uart_data_info = &(p_read_item->data_info);
-    BasicPlcDataInfo *p_base_data_info = &(p_modbus_uart_data_info->base_data_info);    
+    BasicPlcDataInfo *p_base_data_info = &(p_modbus_uart_data_info->base_data_info);   
+    ModbusUartFunctionCode function_code = p_modbus_uart_data_info->function_code; 
 
     ControlPrintfList("SEND", p_base_data_info->p_command, p_base_data_info->command_length);
     SerialWrite(p_base_data_info->p_command, p_base_data_info->command_length);
 
-    read_length = SerialRead(recv_buff, sizeof(recv_buff));
+    if (READ_COIL_STATUS == function_code || READ_INPUT_STATUS == function_code) {
+        cmd_length = 6;
+    } else if (READ_HOLDING_REGISTER == function_code || READ_INPUT_REGISTER == function_code) {
+        cmd_length = 7;
+    } else if (WRITE_SINGLE_COIL == function_code || WRITE_SINGLE_REGISTER == function_code) {
+        cmd_length = 8;
+    } else {
+        //MULTIPLE_COIL and MULTIPLE_REGISTER to do
+        cmd_length = 0;
+    }
+
+    read_length = SerialRead(recv_buff, cmd_length);
     if (read_length) {
         ControlPrintfList("RECV", recv_buff, read_length);
         return ModbusUartTransformRecvBuffToData(p_read_item, recv_buff);
diff --git a/APP_Framework/Framework/control/ipc_protocol/modbus_uart/test_recipe_modbus_uart.json b/APP_Framework/Framework/control/ipc_protocol/modbus_uart/test_recipe_modbus_uart.json
index 613d010c6..1f5cf41de 100644
--- a/APP_Framework/Framework/control/ipc_protocol/modbus_uart/test_recipe_modbus_uart.json
+++ b/APP_Framework/Framework/control/ipc_protocol/modbus_uart/test_recipe_modbus_uart.json
@@ -24,7 +24,7 @@
             "value_type": 9,
             "function_code": 3,
             "start_address": 208,
-            "quantity": 2
+            "quantity": 1
         }
     ]
 }
\ No newline at end of file
diff --git a/APP_Framework/Framework/control/shared/control_io.c b/APP_Framework/Framework/control/shared/control_io.c
index 5fdf3119c..fbb01b7ec 100644
--- a/APP_Framework/Framework/control/shared/control_io.c
+++ b/APP_Framework/Framework/control/shared/control_io.c
@@ -162,7 +162,7 @@ void SerialWrite(uint8_t *write_data, int length)
 
     PrivWrite(uart_fd, write_data, length);
 
-    PrivTaskDelay(10);
+    PrivTaskDelay(15);
     Set485Input();
 #endif
 }
@@ -181,15 +181,11 @@ int SerialRead(uint8_t *read_data, int length)
 
     while (data_size < length) {
         data_recv_size = PrivRead(uart_fd, read_data + data_recv_size, length);
-        // for (int i = 0; i < data_recv_size; i ++) {
-        //     printf("idx %d data 0x%x\n", i, recv_data[i + data_size]);
-        // }
-
         data_size += data_recv_size;
     }
 
-    //need to wait 25ms , make sure write cmd again and receive data successfully
-    PrivTaskDelay(25);
+    //need to wait 30ms , make sure write cmd again and receive data successfully
+    PrivTaskDelay(30);
 
     return data_size;
 #endif
diff --git a/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c b/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
index 43c94addd..428e1c935 100644
--- a/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
+++ b/Ubiquitous/XiZi_IIoT/resources/serial/dev_serial.c
@@ -154,6 +154,8 @@ static inline int SerialDevIntRead(struct SerialHardwareDevice *serial_dev, stru
 
         CriticalAreaUnLock(lock);
 
+        MdelayKTask(20);
+
         *read_data = get_char;
         read_data++; 
         read_length--;