The thermal test for extravehicular spacesuits had the different characters with that of traditional spacecraft. One reason is that the extravehicular spacesuits in orbit are subjected to complex heat flux, and the complex and varied shape of extravehicular space makes it difficult to simulate using traditional methods on the ground. Secondly, during the operation of the extravehicular service, water vapor will be discharged outward. Thirdly, there are many gas-liquid pipelines and measurement and control cables led out from the interior of the extravehicular service during the testing process. A special simulation method of extravehicular spacesuits was presented, based on the characteristics of the thermal design. It’s feasible to validate the thermal design by equivalently simulating the space heat flux as the test thermal boundary and measuring the heat leakage of the extravehicular spacesuit and heat dissipation ability.