The force actuator developed for the active mirror uses DC-motor as driving source. Nanometer micro-displacement driving is achieved by means of gearbox,ball-screw-driven stage and groups of springs. Self-locking is performed by leading screw pair. The high gain PID controller based on pull-push force sensor in the feedback path can provide a sufficiently high loop gain to suppress effect of friction on micro-dynamic characteristics so that an excellent linearity is achieved. The actuators were tested in an active mirror prototype with four same actuators and three rigid supports. The measurement of micro-displacement was tested by an optical interferometer. The results of the prototype show that the average displacement resolution is 10 nm,max stroke is ±8 μm,max driving force is ±700 N. The experimental results show that the force actuator is suitable to drive an active mirror. This also provides basis for further optimization of actuator developed for active mirror.