In order to manage the air-conditioning thermal system, battery thermal system and motor thermal system in a unified manner, the author proposes a self-developed integrated thermal management system for electric vehicles to recover battery energy. Firstly, the problems in the development of electric vehicles and the importance of thermal management system are introduced, secondly, the self-developed thermal management system scheme and the principle of each part are analyzed, the experimental results of thermal system in enthalpy difference chamber are also introduced. The experimental results show that: Under the double evaporation system, when the compressor speed is 4500 rpm, the maximum COP is 2.46, and the maximum COP charge is 1180 g, the maximum heat transfer capacity is 4819 W (wind side heat transfer + water side heat transfer), the evaporation temperature is 5.35°C, the evaporation superheat is 9.5°C, the condensation temperature is 59.3°C, the undercooling degree is 10.4°C, the suction pressure is 280 kPa, and the exhaust pressure is 1694 kPa. In conclusion, the thermal management system has great energy saving effect, which ensures that the electric vehicle range will not be greatly attenuated under winter heating conditions, and meets the requirements of comfort.