Abstract: The power bus is an important component of power supply system of radar products, which needs high reliability, especially the guarantee of welding quality. The power bus used in a radar product is designed with inner thickened copper clad plate, and the aluminum plate is used as the installation base plate. The design of large current and high heat capacity brings great difficulties to the welding of the power bus. In this paper, aiming at the power bus with large current and high heat capacity, the influencing factors of solder hole tin permeability are analyzed and the process solution is proposed. Through the process test, the tin permeability of the electrical connector pin is gradually increased from 20% to 85%, which solves the welding problem and has important reference value for the soldering process.