Resistance spot welding is commonly used for welding products of high quality because of clean welding and short w welding-time. But. conventional spot welders bring about the depreciation of welding products, iuespective of dynamic r resistance characteristics during welding time. This paper discussed dynamic resistance database implementation in t terms of welding performance improvement. On different welding conditions, we compared dynamic resistance, r respectively, about pure iron and Sn-Pb alloy on Copper. Also, it investigated the relation of tensile shear strength and d dynamic resistance in welded workpiece.