Abstract: In order to investigate the resistance of stress corrosion cracking in nuclear power plant’s pipes,residual stress evolution in a dissimilar metal welded pipe before and after repair welding was studied. SA106B steel pipe was welded to Inconel 600 pipe by manual and automatic butt welding methods. After partial grinding of the original weld,a repair welding was introduced at the grinding area by shielded metal arc welding and gas tungsten arc welding,respectively. The contour method was used to measure the hoop and axial welding residual stress of the pipes before and after repair welding,and residual stress distribution of the pipes was obtained. Through the analysis of residual stress in the dissimilar metal pipes before and after repair welding,it was confirmed that the maximum residual stress was less than 415 MPa,which met the relevant requirements of resistance against stress corrosion cracking. The research results were of high relevance to the repair welding of nuclear power plant components.