An electric heating pad for a water tank includes a substrate, a heating layer paved on the substrate, a leading wire that is electrically connected to the heating layer, and a fastener that fixes the leading wire. The substrate is configured with a first through hole that latching to the leading wire. The fastener includes a first fixed part and a second fixed part that are arranged on two faces of the substrate. The second fixed part is configured with a clamp part, and a second through hole matching to the leading wire is arranged at the clamp part. The fastener further includes a connecting rod that connects the first fixed part to the second fixed part, the substrate is configured with a third through hole, and the connecting rod passes through the third through hole to make the substrate be clamped between the first fixed part and the second fixed part.