Abstract: In order to obtain high-strength dissimilar metals joints of T2 copper and Ti-6Al-4V titanium alloy, electron beam welding was used to carry out experiments, and the interfacial microstructure and mechanical properties of the joints were analyzed. Based on the Ti/Cu welding-brazing process, the remelting temperature field of intermetallic compounds layer at the Ti/Cu bonding interface was constructed by secondary composite welding on the Ti side of high melting point, and then the remelting modification of Ti/Cu intermetallic compounds layer was realized. By temperature field simulation of FEM and detection of SEM, XRD, the results shown that a high temperature of about 1 000℃ at the interface was formed by remelting welding at titanium side, leading to local remelting of intermetallic compound layer. In the process of solidification, due to the direction of heat dissipation and the redistribution of elements, the formation sequence of the phase was changed, the diffusion distance of titanium atoms was reduced and TiCu with high hardness was transformed to Ti₂Cu. The phase structure was optimized and finally the strength of the welded joints improved.