Abstract: Residual stress of the multi-layer and multi-pass welding joints of the small-caliber thick-wall 12Cr1MoVG steel tubes was calculated by the finite element modeling (FEM) simulation software and the birth-death element method. The calculation results show that the residual stress in the area near the welding seam of outer wall of welded joint was compressive stress, and the change range of residual stress at the base metal end was smaller than that in the weld area. The residual stress of the inner wall weld and heat affected zone of welded joint was compressive stress, while there was tensile stress in the base metal. Through comparison, it could be seen that the calculation results of the axial residual stress distribution in the inner and outer walls of welded joint were highly consistent with the measurement results, which showed that the numerical simulation method could provide convenient and reliable technical support for the welding procedure qualification of tubular joints.