A preparation method of a copper particle composition includes dissolving a copper carboxyl compound, or a carboxyl group-containing compound and a copper salt, in a solvent to prepare a copper(II) precursor solution; putting a weak reducing agent with a standard reduction potential of −0.2 to −0.05V to the prepared copper(II) precursor solution to assemble a plurality of Cu2O fine particles having an average diameter of 1 to 100 nm with a standard deviation of 0 to 10%, thereby forming spherical Cu2O assembly particles having an average diameter of 0.1 to 10 μm with a standard deviation of 0 to 40%; reducing the spherical Cu2O assembly particles into copper particles by using a reducing agent; and separating the copper particles from the result product. Thus, copper particles can be produced fast, economically, and the obtained copper particles have good crystallinity and good resistance against oxidation.