Abstract: In order to improve wave energy capture capability of the system and analyze the force on the float,approximately fitting the radiation force by the state-space method,the mathematical model of direct-drive wave power system was established. Taking the captured wave energy of the system as the objective function,and solving Hamilton’s equation in the S domain based on the optimal control theory,the singular optimal control rate was calculated,and the ideal electromagnetic force signal was obtained by inverse Laplace transform. Aimed at ensuring the tracking effect of the thrust force and primary flux,combined with direct thrust force control,a second order sliding mode control scheme was designed to ensure the tracking effect of the thrust force and primary flux. The results show that the proposed optimal power scheme has high capture efficiency,the proposed controller has small tracking error and good dynamic performance. It can improve the wave energy conversion rate,effectively reduce the thrust force and primary flux impulse,and optimize the system output power.