The challenge in the artificial CO2 reduction to fuel is achieving high selective electrocatalysts. Here, a highly selective Cu2O/CuO heterostructure electrocatalyst is developed for CO2 electroreduction. The Cu2O/CuO nanowires modified by Ni nanoparticles exhibit superior catalytic performance with high faradic efficiency (95% for CO). Theoretical and experimental analyses show that the hybridization of Cu2O/CuO nanowires and Ni nanoparticles can not only adjust the d‐band center of electrocatalysts to enhance the intrinsic catalytic activity but also improve the adsorption of COOH* intermediates and suppress the hydrogen evolution reaction to promote the CO conversion efficiency during CO2 reduction reaction. An in situ Raman spectroscopic study further confirms the existence of COOH* species and the engineering intermediates adsorption. This work offers new insights for facile designing of nonprecious transition metal compound heterostructure for CO2 reduction reaction through adjusting the reaction pathway. A highly selective Cu2O/CuO heterostructure electrocatalyst is developed for CO2 electroreduction, which exhibits faradic efficiency (95% for CO). The hybridization of Cu2O/CuO nanowires and Ni nanoparticles could improve the adsorption of COOH* intermediates to promote the CO conversion efficiency. An in situ Raman spectroscopic study further confirms the existence of COOH* species and the engineering intermediates adsorption.