Abstract: Aiming at the problem of low control accuracy and poor stability caused by the controller area network (CAN) communication time-varying delay during the rotating speed control phase of the gear shift process, a rotating speed closed-loop control mathematical model with random time-varying delay was established, and the method of using fractional PID to modify the frequency response curve was proposed, which improved the system's adaptability to time-varying delay. Aiming at the time-varying characteristic of time-varying delay and the limitation of fixed-parameter PID, a rotating speed control algorithm based on fuzzy fractional PID was designed. Simulation and experiment results show that the control algorithm achieves better effects.