Abstract: To improve the low velocity control performance of Autonomous Underwater Vehicles(AUVs) , a single gimbal Control Moment Gyro(CMG) is introduced as the attitude control system, the drive system of which consists of four brushless DC motors and four reducer motors. Considering the need of AUV for CMG motors, a steady-speed control system is presented in which the brushless DC motors and worm gear reducer motors are based on TMS320F2812. The DSP controller module, PWM photoelectric buffer module, drive module, JTAG interface module, RS-232 SCI module and software program of the system are included. In building the peripheral circuit, only a single DSP chip is employed to control the starting or stopping and realize the measurement of the working statement of the four brushless DC motors, and the forward or reverse response speed of the worm gear reducer motors can also be accepted. The experiment shows that the designed DSP control system of CMG can satisfy the attitude control requirements of AUVs.