Abstract: The electrical efficiency of the proton exchange membrane fuel cell stack is about 50%. The remaining energy of the electrochemical reaction will be lost in the form of heat,causing huge energy waste. The development of a fuel cellbased cogeneration system can efficiently generate electricity and hot water, and significantly improve the energy efficiency of the system. A 70 kilowatt-level fuel cell cogeneration system was built on the MATLAB/Simulink platform, including fuel cell electrical model, thermal management model and integrated dynamic model of cogeneration system, and an intelligent control algorithm was developed for water and heat management, and the operating temperature of the stack is controlled at about 70 ℃. Under the premise of ensuring the normal operation of the stack, the heat recovery efficiency is improved and the parasitic power of the system is reduced. The results show that the system can effectively recover the waste heat generated by the fuel cell reaction. While increasing the external load to improve the stack efficiency, the cogeneration efficiency will gradually increase and then decrease, and the highest efficiency of cogeneration can reach 83.5%.