Abstract: Copper clad aluminum bus bar was prepared using five stand continuous rolling system and heat-treated by different processes, the Cu/Al boundary layer was observed using optical microscope, and hardness of the boundary was tested using micro-hardness tester, the chemical composition was tested using EDX. The results showed that cooling process played less impact on the performance of boundary layer, but temperature had a bigger impact. And Brinell hardness on the surface of bus bar was lower than that of copper layer.