In order to correct the atmospheric disturbance around the main mirror and the error caused by wind, the calibration frequency must reach 10 Hz in the active optics system. Therefore, the force actuator must have good dynamic response and high-precision positioning. A new scheme of force actuator, in which linear voice coil motor is used as the driver and linear grating is used as the displacement sensor, is proposed in this paper. With using the deadbeat control theory, the force actuator could achieve fast response, no steady-state error, small overshoot, rapid recovery, and high-resolution which cannot be deeply improved by the traditional PID control method. Finally, the calibration frequency can reach 20 Hz which has met system design requirements. Simulation and experiment demonstrates that this kind of control method can effectively improve the performance of the force actuator.