Abstract: The residual temperature field and residual displacement field of a T joint were analyzed in this paper. By adopting the sequential coupling analysis, we designed a self-adaption cut-off technique for different materials and structures. Basing on the material properties of S355J2G3, we made the threshold optimization of cutting temperature and established the evaluation method for simulation performance. The results show that the optimal cut-off temperature obtained by this method. In this paper, the simulation results are almost identical with experiment. The self-adaption cut-off temperature technique is ascertained the validity of evaluation method, which improves the accuracy of the displacement solution and decreases the computation time. By using this method in the welding numerical simulation which could realize the efficiency and accuracy. Also, this method could extend to bogie frame of high-speed trains and other large structures.