The process of solder joints on the gold-plated surface of Sn-Pb solder was widely used in aerospace electronics. The requirements of gold content in solder joints after welding in industrial documents and domestic and foreign standards were analyzed. The influences of solder gold content, aging and different packaging forms on reliability of solder joints were analyzed and the metallographic structure of solder joints was discussed. Finally, the requirements of de-golding and failure case of inadequate de-golding were introduced.