Wave energy resources have abundant reserves and broad development prospects, but the low energy extraction efficiency has permanently restricted its commercial development process. Based on this, an improved model predictive control (IMPC) approach utilizing the interior point method is proposed to optimize the energy extraction of the wave energy generation system. By establishing the optimal control model of the wave power generation system, the objective function is optimized to improve the energy absorption efficiency, and the inequality constraint conditions of the objective function are transformed into unconstrained conditions for rapid calculation. To verify the advantages of the proposed IMPC, simulations were conducted to compare it with traditional model predictive control (TMPC) and generalized predictive control (GPC). Simulation results indicate that the energy extraction efficiency of the proposed IMPC is significantly better than that of TMPC and GPC, and its calculation speed does not decrease significantly as the computational burden increases.