Constructing　heterojunction　interface　as　an　active　catalyst　is　an　effective　strategy　to　boost　electrocatalytic　activity　of　oxygen　evolution　reaction(OER).Herein,we　report　an　interfacial　CoP/CeO2　heterostructure　catalyst　constructed　by　interface　engineering　and　selective　phosphorization　procedure.X-ray　photo-electron　spectroscopy(XPS)suggests　that　coupling　CeO2　nanoparticles　on　the　surface　of　CoP　will　generate　interfacial　interaction　at　the　two-phase　interface,resulting　in　electron　transfer　between　CoP　and　CeO2　components　at　the　interface.Benefitting　from　the　interfacial　interaction,large　exposed　inter-face　area,and　luxuriant　mesopores　structure,CoP/CeO2　shows　fascinating　alkaline　OER　performance.At　the　current　densities　of　10　and　50　mA　cm-2,the　optimal　CoP/CeO2　heterojunction　exhibits　lower　overpotential(257　and　298　mV)than　either　CoP(288　and　354　mV)or　RuO2(305　and　409　mV).This　work　provides　a　facile　synthetic　protocol　for　constructing　heterostructure　interfaces　to　improve　OER　performance.