Nanoporous copper with nano-scale pore size was synthesized by dealloying Mn-Cu precursor alloy using a free corrosion method.The effects of heat treatment of Mn-Cu precursors on alloy phase,morphology and composition of the resultant nanoporous copper were investigated.It is revealed that the compositions distribute homogeneously in the bulk Mn-Cu precursors,which consequently results in a more fully dealloying for forming nanoporous copper.The alloy phase changes from Cu0.49Mn0.51 and Cu0.21Mn0.79 of non-thermally treated precursor to Cu0.33Mn0.67 of heat treated alloy.The residual Mn content in nanoporous copper is decreased from 12.97％ to 2.04％ (molar fraction) made from the precursor without and with 95 h heat treatment.The typical pore shape of nanoporous copper prepared by dealloying the precursor without the heat treatment is divided into two different zones:the uniform bi-continuous structure zone and the blurry or no pore structure zone.Nanoporous copper is of a uniform sponge-like morphology made from the heat-treated precursor,and the average ligament diameter is 40 nm,far smaller than that from the non-thermally treated precursor,in which the average ligament diameter is estimated to be about 70 nm.