A method for electrodepositing copper nanoparticles includes the steps of a) providing a reaction system having an electrolyte solution, a conductive nitride film used as a working electrode and immersed in the electrolyte solution, a copper metal or a copper alloy used as an auxiliary electrode and immersed in the electrolyte solution, and a reference electrode immersed in the electrolyte solution; and b) applying a pulse voltage to the reaction system to form copper nanoparticles on a surface of the conductive nitride film.