Abstract: The thermal design of heat sink structure for multi-density and high-power chip is studied by ICEPAK software in this paper. The key dimension design parameters which affect the heat dissipation performance of heat sink, such as the base plate thickness, the fin height, the fin thickness and the fin spacing, are established, the effect trend of heat sink dimension design parameters on its heat dissipation is obtained and the optimal structure layout of the heat sink is determined. In addition, the optimal layout of heat sink structure is established and high and low temperature experiments are carried out to simulate its high temperature heat dissipation in the study. By comparing with experimental data, it is found that the simulation results are in good agreement with the practice, which further validates the accuracy and reliability of ICEPAK software in the heat dissipation design of electronic equipment.