A light source board includes a substrate; a metal reactive layer disposed on the substrate; a metal conductive layer disposed on the metal reactive layer; a metal alloy layer disposed on the metal conductive layer; and at least one light source disposed on the metal alloy layer. A material of the metal reactive layer is a Sn—Bi type alloy or a Sn—Ag—Cu type alloy, and arrangements of materials of the metal reactive layer and the metal conductive layer are respectively an arrangement of silver paste and copper, an arrangement of silver paste and nickel, an arrangement of silver paste and silver, an arrangement of copper paste and copper, an arrangement of copper paste and nickel, or an arrangement of copper paste and silver.