The frame motor of the control moment gyro requires high control precision, fast mechanical response, low rotation speed and small mass, and can adapt to the working environment of high vacuum and high temperature difference. In order to meet the abovementioned requirements, a special mode ultrasonic motor is designed for the control moment gyro to drive the moment gyro frame in this paper. Based on the finite element method, the size of the prototype was calculated and optimized, and the speed and load characteristics of the motor are tested and optimized. The ultrasonic motor is composed of an ultrasonic motor stator, a moment gyro shaft and a base. The stator is fixed to the base by a hinge, and the spring mechanism applies a prepressure thereto. The ultrasonic motor has a mass of 25 g and an output torque of 0.04 N·m, which satisfies the requirements for the control moment gyro.