A metal nanoparticle which is prepared by forming a self-assembled monolayer including a terminal reactive group on the surface thereof, and introducing a functional group capable of being removed by the action of an acid or an base into the terminal reactive group wherein the self-assembled monolayer is built up of a thiol, an isocyanide, an amine, a carboxylate or a phosphate compound having the terminal reactive group, or built up of a thiol, an isocyanide, an amine, a carboxylate or a phosphate compound having no terminal reactive group followed by introducing the terminal reactive group thereto; and a method for forming a conductive pattern using the same are provided. Since the metal nanoparticle of exemplary embodiments of the present invention can easily form a high conductive film or a high conductive pattern through photo-irradiation and photo-degradation and randomly regulate its conductivity when occasions demand, it can be advantageously applied to an antistatic washable sticky film, antistatic shoes, a conductive polyurethane printer roller, an electromagnetic interference shielding, and the like.