Abstract: In order to obtain the heat source parameters of submerged arc welding in different current and voltage,the double ellipsoid heat source was rewritten.The heat cycle of submerged arc welding was calculated with the deflection of the arc.According to the experiment and simulation results,the pattern search method was applied to obtain the heat source parameter in different welding current and voltage.The simulation heat cycles are similar to the experiment heat cycles.The error of triple-wire welding was lower than 5%.It proves the accuracy of heat source parameter obtained by the pattern search method.