The invention provides a metal nanosheet and a manufacture method thereof. The method comprises the step of carrying out pressurizing treatment on at least two metal sheets for multiple times so as to obtain a multi-layer metal nanosheet, wherein metal elements contained in the at least two metal sheets are not the same completely. The method provided by the invention has the advantages that the multi-layer metal nanosheet can be quickly manufactured on large scale, the cost is low, the operation is simple and convenient, the requirement on equipment is extremely low, and the thickness of the metal nanosheet can be adjusted and controlled by controlling the times of pressurizing treatment.