The TA1/304L dissimilar joint needs to undergo a high temperature environment of about 800 ℃ during colinear continuous rolling of titanium and steel. This article first uses V as the intermediate layer for laser welding to obtain a TA1/304L joint (J_V) with partially melted V as the intermediate isolation layer. Its room temperature tensile strength is equivalent to that of the TA1 base material, but after insulation at 800 ℃ for 30 minutes, the J_V joint directly cracks and fractures in the weld zone (FZ_SV) between 304L and V. Further laser welding is carried out using V+Cu as the intermediate layer to obtain a TA1/304L joint (J_VC) with a composite intermediate layer. V partially melts and acts as an isolation layer, while Cu completely melts into the FZ_SV region. The tensile strength of the welded J_VC joint reaches 0.92% that of the TA1 base material, and after insulation at 800 ℃ for 30 minutes, the tensile strength of the J_VC joint is about 79% that of the TA1 base material. In both cases, the specimen fractures in the weld zone between V and TA1 (FZ_VT). The analysis results indicate that after insulation at 800 ℃ for 30 minutes, a large amount of FeV brittle phases are generated in the FZ_SV weld zone of the J_V joint. When Cu+V is used as the intermediate layer, Cu entering FZ_SV can effectively suppress the generation of FeV brittle phases in the FZ_SV region during the heating process, thereby improving the tensile strength of TA1/304L joint after heating.