The present invention provides a process for producing copper nanoparticles, comprising steps of: a) reacting an aqueous solution containing a reductant with an aqueous solution of a copper salt while stirring for 1-8 min, wherein the reductant being one or more selected from a group consisting of hydrazine hydrate, sodium borohydride and sodium hypophosphite; b) adding an apolar organic solution containing the extracting agent and continuing the stirring for 0.5-1.5 hrs, said extracting agent being one or more selected from the group consisting of alkyl dithiocarbonic acid and salts thereof, O,O'-dialkyl dithiophosphoric acid and salts thereof, and dialkylamino dithioformic acid and salts and said apolar organic solution being one selected from the group consisting of benzene, toluene and straight or branched alkanes having 6-12 carbon atoms, wherein the alkyl having 6-20 carbon atoms; and c) post-treating the reaction product to obtain copper nanoparticles.