Abstract: With the development of aerospace electronic products towards miniaturization and integration, the heat flux of products is increasing rapidly. The problem of thermal shock resistance and heat dissipation has become one of the bottleneck problems restricting product design. Phase change temperature control technology can solve the problem well, and phase change temperature control is passive temperature control, high reliablity, meet the requirements of aerospace products. In this paper, a VPX standard chassis heat expansion plate structure is taken as the research object, and the composite structure of phase change material and load product is proposed. The temperature control performance of the phase change temperature control device was tested through design experimets, and the heat storage capacity of the phase change temperature control device was simulated though finite element simulation modeling.The thermal performance of the phase change temperature control device with six different filling amounts of phase change materials and different thermal conductivity enhancers was obtained. The test results show that the thickness of the heat expansion plate, that is, the amount of phase change material, has the greatest influence on the heat storage capacity of the phase change device, followed by the same amount of phase change material, carbon foam composite phase change plate has the strongest heat storage capacity, followed by copper foam, expanded graphite has the worst performance. The simulation results are consistent with the experimental results, which proves the rationality and validity of the simulation parameters of the phase change process. It can provide empirical data reference for subsequent thermal simulation of phase change process.