The invention belongs to the technical field of energy storage batteries and relates to a double-layer negative current collector for a liquid metal battery. The double-layer negative current collector comprises an electrode rod, a foam alloy A impregnated with lithium, and a foam alloy B which is not impregnated with the lithium, wherein the foam alloy A and the foam alloy B coaxially sleeve the bottom of the electrode rod in sequence from top to bottom; through a nut arranged at the upper part of the foam alloy A and a nut arranged in a bottom groove of the foam alloy B, the foam alloy A and the foam alloy B are fixed at the bottom of the electrode rod; and the nuts, the foam alloy A and the foam alloy B are tightly laminated. The invention further discloses a preparation method of the double-layer negative current collector. According to the double-layer negative current collector, the structure can be mechanized on a large scale while the foam alloys are effectively fixed, assembly is simple, the machining precision is controllable, and improvement of the shape consistency of the negative current collector structure for the battery is facilitated.