Abstract: On the basis of the thermal-elastic-plastic theory, a three-dimensional finite element numerical simulation residual stress of girth welded duplex stainless steel pipes with ANSYS non-liner finite element program. Three-dimensional FEM using mobile heat source for analysis transient temperature filed and welding stress filed in circumferential joint of pipes is founded. Distributions of axial and hoop residual stresses of the joint are investigated. The axial and the hoop residual stresses at the weld and weld vicinity on inner surface of pipes are tensile, and gradually transferred into compressive in base metal. The axial residual stresses at the weld and weld vicinity on outer surface of pipes is compressive while the hoop one is tensile. The distributions of residual stresses compared positive semi-circle with negative-circle show distinct symmetry. These results provide theoretical knowledge for the optimization of welding process and the control of welding residual stresses.