Abstract: Using the finite element method,a model of temperature field of weld repaired,which is simplified,is established in the paper.The weld stress consists of thermal stress and organization stress.Models of the thermal stress and organization stress are describled. ANSYS,a software of finite element,is applied to calculate and simulate the stress.BHW35 is taken as an example.It is proved that the simulated calculation data is close to that measured.It is the conclusion that the stress in welding center line changed little,the stress in HAZ became higher,and the value of stress in HAZ and the width of HAZ increased with increasing of the number of weld repaired.The weld residual stress by PWTH is discussed in order to prove that PWTH can really improve the distribution of stress.