It is of great importance to design and develop highly active electrocatalysts for the hydrogen evolution reaction (HER) under alkaline conditions. In this work, we report the development of a CeO2-Cu3P nanoarray supported on nickel foam (CeO2-Cu3P/NF) as an excellent HER catalyst with the demand of an overpotential of only 148 mV to deliver a geometrical catalytic current density of 20 mA cm-2 in 1.0 M KOH. Remarkably, this catalyst also shows strong long-term electrochemical durability for at least 100 h with nearly 100% Faradaic efficiency. Density functional theory calculations reveal that the CeO2-Cu3P/NF hybrid has a lower water dissociation energy and a more thermo-neutral hydrogen adsorption free energy.