In order to meet the requirements of passive heat dissipation of laser source in aerospace applications, project of heat dissipation solution of high power devices in laser source is proposed. The heat conduction channel from device and printed circuit board to metal structure is designed, which can transfer heat from devices to metal structure efficiently, ensure that the device temperature is within the normal operating range. Efficiency of heat dissipation can be promoted by ways of evolving structure and material of laser soucrce, and by ways of adding or evolving dissipation passages. Simulation results show that, when working in high temperature circumstance, In the heat dissipation optimized scheme, the maximum temperature of chip and laser is reduced by about 100 ℃ and 1 ℃ respectively, the optimized project is effective and viable.