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.(c)　2023　Chinese　Society　of　Particuology　and　Institute　of　Process　Engineering,　Chinese　Academy　of　Sciences.　Published　by　Elsevier　B.V.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://　creativecommons.org/licenses/by-nc-nd/4.0/).