Compared with the traditional vector control, the drive signal is directly obtained by the finite control set model predictive control (FCS-MPC) through the algorithm. The method omits the pulse width modulation link, and has superior response performance. The transfer function of the control system only containing the speed loop is constructed by the improved FCS-MPC algorithm. In the load changes and parameter disturbance conditions, the frequency characteristic analysis method of the transfer function and the typical system tuning method are used to design the PI self-tuning control system based on the speed loop. Simulation comparison and verification show that the proposed method has smaller fluctuation of the speed change caused by the load torque and parameter changes and recovers faster than the traditional control. The results verify the feasibility and effectiveness of the method.