Abstract: A nanopoporous copper was synthesized by free corrosion dealloying in the 0.1 mol/L HCl solution. Micro-structure and composition of the sample before and after dealloying were characterized by a scanning electron microscope and an energy dispersive analysis of X-ray. There was selective dissolution of manganese from Mn-Cu alloy in the 0.1 mol/L HCl solution, and the nanoporous copper with a uniform porous structure in three-dimensional network, an average ligament size of 53 nm and an average pore size of 140 nm was prepared.