The electronic equipment on missile is small in size, light in weight, high in heat consumption, and adiabatic with the outside, so the problem of heat dissipation is a big problem.The integrated design of heat dissipation structure and heat transfer path optimization of phase-change materials were carried out based on the characteristics of the short-time working of the electronic equipment on missile and the high latent heat of phase-change materials, and the problem of heat dissipation of the electronic equipment on missile was solved by phase-change energy storage.In order to evaluate the heat dissipation effect and thermal design compliance of PCM structures as heat sinks, a transient simulation method was proposed to calculate the equivalent specific heat capacity of the phase change process. The simulation results were verified by experimental tests. The maximum difference between the simulation results and the experimental results was 2.47%, which was 2.5℃.The experimental results show that the simulation results are accurate and the calculation method of equivalent specific heat capacity of phase-change materials is feasible, which provides a new idea and method for the transient simulation of phase-change heat sink structure of electronic equipment.