As the core device of the electronic valve, the operating state of the micro permanent magnet stepping motor has a direct impact on whether the electronic valve can perform operations normally. In order to accurately grasp the remaining useful life of the motor, a prediction method considering individual differences in the Wiener process is proposed. Firstly, by analyzing the failure process of motor performance degradation, the effective value of phase current is selected as the characteristic quantity of performance degradation. Secondly, due to the simultaneous participation of multiple motors of the same model in the experiment, a motor performance degradation model considering the individual differences in the Wiener process is established, and parameter estimation is carried out based on the EM algorithm.Finally, the number of starting and stopping times is designed as the reference of the motor′s remaining useful life in the experiment and compared with the prediction results based on the traditional Wiener process. The experimental results show that the average prediction error of the proposed method decreases by 3.74%, which has a higher prediction accuracy.