In the laser beam stabilizing system, there are the broadband disturbance where energy is inversely proportional to the frequency and the narrowband disturbance at a particular frequency because of the transfer medium and vibration of the optical platform. In order to reduce the laser beam jitter caused by both kinds of disturbance, the control structure of fast steering mirrors (FSM) in series was put forward, and the control algorithm was presented, in which the first laser beam stabilizing system aimed to the narrowband disturbance, and the second laser beam stabiliting system resolved the broadband disturbance. So the disturbance can be restrained at the same time. The residual errors are compared between the proposed method and the classic control algorithm, and the simulation results and experimental results verify the availability of the proposed method.