Abstract: The full IMC solder joint in the electronic packaging has higher mechanical and electrical properties than the traditional residual solder joint, so it can meet more demanding service conditions and has a broad application prospect. The preparation methods of the full IMC solder joint of Cu-Sn system and its welding technologies were summarized. In addition,the technologies for preparing full IMC solder joint were compared and analyzed from three aspects including the microstructure evolution, the growth mechanism of IMCs and the mechanical properties of solder joint, so as to make a prospect for the development direction of the technology of full Cu-Sn IMC solder joint.