Abstract: In order to avoid the influence of external heat flow interference between multiple satellites in the multi-satellite thermal balance thermal vacuum test of microsatellite products, a movable cold plate heat sink is designed, consisting of a cold plate, skeleton, guide rail pulley, and liquid nitrogen pipeline connection system. The design of a movable cold plate heat sink is described briefly, and thermal load calculation and simulation analysis on the cold plate are carried out. The analysis results show that when the thermal load on the front and back surfaces of the cold plate is 1 000 W, the temperature of the cold plate is below 100 K. In the experimental verification, different heat flux values are applied to the cold plate, and the temperature of the cold plate meets the test requirements. The test results indicate that it can be used as a heat sink component in the multi-star thermal balance test and thermal vacuum test.