The ocean thermal energy is abundant. The global total is about 40 billion kW. The ocean thermal energy conversion (OTEC) is clean and renewable, the power generation is stable, and the energy storage has high capacity. Active exploitation of ocean thermal energy resources is of great significance to realize the strategy of maritime power. In view of the efficiency limit of a traditional OTEC, authors propose an approach of a multi-energy complementary OTEC system that they can improve the efficiency of this system. The approach sets parameters at the system level and integrates solar energy, wind energy, energy storage and OTEC. For example, a 1MW integrated power generation system is designed and simulated by means of computer aided design and of conducting a model-based simulation, respectively. The efficiency of the complementary OTEC system with solar heating can reach 13.12%. In this article, the basic principle and working process of the approach are analyzed, and the system efficiency is calculated. The results show that, in comparison to the traditional OTEC, the complementary system of OTEC can improve the ratio of power generation output efficiency, stability and ocean energy utilization.