Abstract: The heat dissipation performance of natural air-cooling electronic device is closely related to its thermal structure. In this paper, the influence of fin structures of natural cooling on the performance of heat transfer are numerically investigated and compared by using FloEFD software. To enhance the natural heat transfer performance and decrease the temperature of heat sources, a cooling structure with curved surface fins is designed based on chimney effect, without increasing the fin weight. Simulation results show that compared with straight fin, the curved fin structure can effectively use the entrance effect to enhance the natural convection and heat transfer, the chimney structure formed by fins and cover plate can speed up the air flow, which is of great benefit to heat transfer. The heat transfer performance of the heat sinks with straight fins and curved fins are compared experimentally. The result indicates that under the same heating power, the heat source temperature decreases by more than 3 ℃ after optimization. The study can provide a reference for efficient natural air-cooling design of electronic equipment.