Abstract: To improve the trajectory tracking control accuracy of the AMT clutch pneumatic actuator and the comfort of the AMT automatic transmission vehicle during starting and shifting, the mechanical equation and load characteristics of AMT clutch pneumatic actuator system were analyzed, and a method for calculating the engaging speed of the AMT clutch was proposed. The method is based on the gas equation and mechanical equation of actuator system, and the clutch engaging speed can be calculated under different engaging positions and different equivalent opening degrees of the exhaust valve. The control system of the clutch actuator is described as a two-input single-output system. Then the clutch actuator test bench is set up to verify the method, and the calculated results are compared with the measured data. The results show that the calculated values are basically consistent with the measured data, except for special working conditions, the calculation error of the engagement speed is mostly less than 10%, and the accuracy can meet the needs of the AMT clutch control. A clear relation is established between the control quantity (the equivalent opening of the exhaust valve) and the actual physical parameter of the clutch engaging speed, which has practical value for the trajectory tracking control of the clutch actuator.