Abstract: The influence of heat treatment process on the interface thickness,interfacial bonding strength and the compounds change of Cu/Al-3.25Si cold-press joining was investigated by measuring the mechanical properties and observing microstructure. The results showed that the inter-layer thickness was firstly growing quickly with the increase of heat treatment temperature and holding time, and then it was growing slowly. The kinetics of the diffusion layer growth hasa index of 0.5-1. The interfacial shear strength is also growing quickly with the increase of heat treatment temperature and preservation time and then slowly. The intermetallic compounds is Cu₉Al₄, CuAl, CuAl₂ from the copper side to the aluminum side under the optimum condition of 300 ℃×2 h.