In order to improve the stability precision of the electro-optical stabilized platform,a nonlinear integral sliding mode control method is proposed,which can solve the problems of the steady-state error of the conventional sliding mode control,as well as large overshoot,long adjustment time and poor transient performance of the conventional integral sliding mode control.Adopting new reaching law can improve the response speed and reduce the chattering.Moreover,the nonlinear integral sliding mode surface is added to sliding mode observer to improve the anti-disturbance ability of the system.Simulation results show that the proposed method can track the input instructions more rapidly and accurately without overshoot in comparison with conventional sliding mode and integral sliding mode.By using this method,the stabilization accuracy of the line of sight is improved by 28.43% compared with that of the conventional sliding mode.Therefore,the control algorithm designed not only improves the dynamic performance of the system,but also improves the stability accuracy of the platform.