Converting CO₂ to value-added chemicals and fuels by the electrocatalytic reduction reaction (CO₂RR) is a promising strategy for reducing CO₂ emissions and achieving clean energy storage. Herein, Cu₂O catalysts with various morphologies (hexapod concave rhombic dodecahedrons microcrystals enclosed with (331), (111) and (100) facets (D-Cu₂O), cubic microcrystals enclosed with (100) facet (C-Cu₂O) and octahedron microcrystals with (111) and (100) facets (O-Cu₂O)) are prepared via the wet chemical reduction method. The in-situ formation of D-Cu₂O/Cu, C-Cu₂O/Cu and O-Cu₂O/Cu surface/interface and the conversion mechanism of CO₂ to C₂₊ products have been systematically studied. The electrocatalytic performance of D-Cu₂O/Cu for CO₂ to form C₂₊ products is superior to that of C-Cu₂O/Cu and O-Cu₂O/Cu, which the Faraday efficiencies (FE) of C₂₊ products (ethylene and ethanol) reaches 70%. The experimental results combined in-situ Raman spectroscopy and density function theory (DFT) calculations demonstrate that the good electrochemical performance is relate to the surface reconstruction and facet interface, which provides a positive local electronic environment to enhance the adsorption of *CO intermediates and reduces the energy barrier for the activation the C-C coupling. This study will provide a new approach to improve the selectivity of CO₂RR by interface engineering and surface.