The follow-up system of a maritime weapon is nonlinear under the influence of unknown disturbances.To solve the problem,a nonlinear predictive control strategy based on Sliding Mode Disturbance Observer (SMDO) is proposed.The compound control algorithm uses SMDO to approximate the fluctuation of sea waves,load variation and system uncertainty,and then conducts feedforward compensation and model correction of predictive control based on the output of the observer,which keeps the rolling optimization of predictive control close to the actual system,so as to improve the performance of the whole control strategy.When designing the SMDO-based nonlinear predictive controller,the predictive control method for the nonlinear system based on a continuous time period is adopted and then combined with SMDO,so that the design of the composite control law for stability control of the firing line of maritime weapons is finally completed.The simulation results show that the control strategy can effectively improve the anti-jamming ability,hit accuracy and dynamically-stable aiming performance of maritime weapons.