Oxidation kinetics of copper nanowires (CuNWs) with diameter 25 ± 4 nm were studied. The dry powder of CuNWs before oxidation comprises 73.2 wt% Cu and 26.8 wt% Cu2O. The oxidation reaction can be divided into two stages at weight of 111.2%. Oxidized CuNWs after Stage 1 consist of Cu2O and CuO. Oxidized CuNWs after Stage 2 comprise CuO only. The activation energies for both stages are determined by Kissinger method and other five isoconversional methods: Flynn–Wall–Osawa, Starink, Kissinger–Akahira–Sunose, Boswell and Friedman differential methods. The isoconversional activation energies determined by Starink method are used to fit different master plots. The Johnson–Mehl–Avrami equation gives the best fit. Surface atoms are the sites for the random nucleation, and the crystallite strain in CuNWs is the driving force for the growth of nuclei during the oxidation process.