Abstract: Resistance spot welding is a widely used jointing technique during the process of automobile body assembly.The efficiency of spot welding process under continuous work conditions is depended on the electrode life which is related with the effect of water cooling.The fluent flow of cooling water in the cooling cavity has been simulated by using numerical simulation method. Analysis about heat convection and cooling effect of electrode have been performed as the base for the further researches of the increasing of cooling effect and the extending of electrode life.