Interfacial engineering has emerged as a critical approach for tailoring catalytic systems through precise regulation of charge transfer and surface properties. However, construction of well-defined and functionally coupled heterointerfaces to enhance electron transport efficiency, as well as the in-depth understanding of intrinsic relationship between interfacial coupling effects and electrocatalytic performance, remain significant challenges. In this work, a tightly coupled CeO₂/β-Ni(OH)₂ heterojunction catalyst was constructed via in-situ electrodeposition method, enabling efficient electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF). CeO₂ modulated the electronic structure and surface properties of β-Ni(OH)₂ through a synergistic coupling mechanism between Ni³⁺-O moieties and Ce³⁺ species. The resulting heterojunction structure exhibited a pronounced built-in electric field, accelerating NiOOH formation and selective adsorption of substrate molecules. Meanwhile, the incorporation of CeO₂ significantly improved the hydrophilicity and reaction kinetics. This study offers new insights into the structure−activity relationship of interfacial charge transfer in heterostructured catalysts and provides guidance for future electrocatalyst design.