To improve the anti-overload capability of the ultrasonic motor used for the control of guided-ammunition steering gear, by selecting the stator support of the weakest part of the ultrasonic motor as the research object, and taking its thickness, position and width as the design variables, using the finite element method to simulate the high overload environment of 10 000 g(g=9.8 m/s2) produced when firing artilleries, studying the anti-overload capability supported by different stator parameters, so as to a reasonable structure of the ultrasonic motor stator was designed in this paper. The high overload impact deformation of the stator before and after the optimization was obtained through the Machete hammer test, and the output performance of the ultrasonic motor with two stators after the impact deformation was tested by the hysteresis dynamometer. The test results showed that the ultrasonic motor with optimized stator structure had better output performance after large overload impact.