In order to solve the problem of general fins and rudders being lower at low moving speed, the moving mass technical is applied onto AUV, thus to radically solve the weakness of control method with fin and rudder. The space dynamics model of moving mass control is created for AUV. And based on this, the moving mass control system is designed with the sliding mode variable structure control method so as to ensure system tracking error zero convergence. By controlling the moving mass movement with moving mass control system, the attitude of AVU is previously controlled. And simulation result proves that moving mass control system will control the AUV attitude angle precisely and rapidly.