The invention relates to a conductive connecting piece for a battery and a preparation method of the conductive connecting piece. The conductive connecting piece is made of a laminated composite metal material; a concave part is formed in the back side of a resistance spot welding area in the conductive connecting piece; the laminated composite metal material comprises a copper layer and a first corrosion-resisting easily welded metal layer which is compounded on a first side of the copper layer; the front side of the resistance spot welding area is positioned on the first corrosion-resisting easily welded metal layer. The preparation method comprises the following steps: S1, preparing a copper-based laminated composite metal strip material; S2, selectively etching the copper-based laminated composite metal strip material so as to form the concave part; and S3, performing stamping molding on the etched copper-based laminated composite metal strip material, thereby preparing the conductive connecting piece. The conductive connecting piece is easy to weld, good in conductivity, high in production efficiency and low in cost, and also can meet high magnification and large-capacity application places such as a power battery.