Abstract: According to the demand of the heat sink temperature adjustment in the large space environmental simulation for spacecraft, this paper, based on a review of the current development of GN₂ heat sink temperature adjustment, proposes a design of a GN₂ temperature adjustment system for a space environmental simulator. Analysis is made for the critical parameters that affect the system performance, such as the circular flow of the GN₂, the volume flow rate of LN2, the pipe diameter for gas supply, etc. Then the whole system is implemented and put into system debugging. It is shown that the uniformity of temperature is within ±5℃; the temperature rising and the cooling power reaches or exceeds 1℃/min, which meets the demand of test for certain spacecraft.