diff --git a/src/radio_ctrl/src/radio_ctrl.cpp b/src/radio_ctrl/src/radio_ctrl.cpp
index ac957cc..88d0419 100644
--- a/src/radio_ctrl/src/radio_ctrl.cpp
+++ b/src/radio_ctrl/src/radio_ctrl.cpp
@@ -100,7 +100,7 @@ private:
                 else
                 {
                     msg.brake = 0;
-                    msg.rpm = static_cast<uint16_t>(MCU_RPM_MAX * (ch_data[1] - speed[1]) / (speed[2] - speed[1]));
+                    msg.rpm = static_cast<uint8_t>(MCU_RPM_MAX * (ch_data[1] - speed[1]) / (speed[2] - speed[1]));
                 }
 
                 // 一键清扫