Abstract: Based on SYSWELD software, a 3-D finite element simulation is performed to investigate the temperature field and residual stress in the repair weld process of P92 plate. The results show that large tensile residual stresses are genetated in the repair weld and heat affected zone, and decrease in the base metal gradually. With the increase of repair length, the transverse residual stress decreased in the middle of plate surface, HAZ and weld metal.The longitudinal stess shows a declining trend in weld matal with the increase of repair length, while in the middle of plate surface and HAZ, it is affected a little by the repair length.