Abstract: Active thermal control technologies were used in extravehicular mobility unit(EMU).The configuration of EMU is complicated and there are many influence factors on reaching heat flux.The thermal test for EMU had the different characters with that of traditional space probe.Different simulation methods of EMU thermal test were 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 EMU and heat dissipation ability.