Objective The effects of the overlapping rate of laser spots on the residual stress distribution after laser shock processing ( LSP ) were investigated. Methods The surface of AISI202 stainless steel welding joint was processed by LSP with different overlapping rates of laser spots. The residual stress of welding joint treated by LSP was determined by the X-ray diffraction method. Results The residual stress was enhanced and its distribution became more uniform when the overlapping rate increased. As the overlapping rate increased from 50 % to 80 % ,the average of landscape orientation residual compressive stress σ_y was improved by 20 % and its fluctuation was decreased by 30 % , while the average of longitudinal direction residual compressive stress σ_x was improved by 30 % and its fluctuation was decreased by 13 % . Conclusion The distribution of the residual stress of welding joint treated by LSP can be optimized by increasing the overlapping rate.