The paper focuses on the heat dissipation efficiency problem existed with LED automobile headlamps. Based on computational fluid dynamics, Ansys-icepak is used to build plug-in fin and cylindrical fin models for LED headlamp heat dissipation structures. During simulation and optimization, the model′s geometric parameters are set as variables, highest temperature and mass are set as constraint functions, thermal resistance is set as objective function. The result indicates that under the same boundary condition with 85 ℃ initial temperature, the plug-in fin model has mass of 0.2756 kg, temperature rise of 12.52 ℃ and thermal resistance of 1.026 ℃/W, which is better than cylindrical fin model, and accords with the heat dissipation standard of LED headlamp. During design in headlamps, an input air grill and an outlet are arranged at the front bottom and upper back of the headlamp respectively, the opposite direction wind generated from the moving automobile is taken to strengthen internal convection. The results show that when velocity is 2 m/s in grade one, the temperature rise is less than 10 ℃, which reflects higher heat dissipation efficiency.