Abstract: There is a definite correlation between the welding residual stresses and deformations,which can be connected by the incompatible strains formed in the welding process.Based on the initial welding strain,a math model of 2D welding residual stresses determination was deduced through direct boundary clement method.If the value of the initial welding strain was given,and in light of the measured boundary displaces,all the unknown displacemcnts and traction at the boundary could be calculated by using the boundary integral equation.Thereby,by using the model,the residual stresses of the weld structure could be solved.The stresses at the boundary can be calculated by the physical equation and the geometric equation according to the correlation between the stresses and the traction at the boundary.The feasibility of the model was verified through a concrete computing instance.