The control system of automatic clutch is based on the manual gearbox instead of the clutch pedal. It realizes automated clutch and manual shifting. The essence of automatic clutch is how to control the motor drive unit to achieve the implementation of the automatic clutch separation and bonding, and thus automatic speed technology of motor is the key. In this paper, combining the characteristics of micro-car, a double-loop automatic motor speed control system is designed. The design is proved reasonable and feasible through simulation based on MATLAB.