Abstract: In order to figure out the residual distortion of welded tubular structure, a thermal-elastic-plastic model using commercial FEA software MSC.Marc was established by considering material nonlinearity and geometry nonlinearity. The active and death element method was employed to simulate the welding process of shell plate and two tubes at different locations, respectively. The results show that the welded tube exists swelling distortion with its axial line offset, and buckling deformation occurs in the shell plate near weld. Before simulation, the rationality of the input parameters were discussed by comparing the experimental and simulated results of butt joint in three aspects of thermal cycles, longitudinal and transverse residual stresses of certain locations and angular distortion.