Underlying the electrocatalytic mechanism has profound influences on designing novel efficient electrocatalytic interfaces and improving the efficiency of electrocatalytic degradation. In this study, a novel PbO2/Y2O3 nano-composite anode with hybrid interface was successfully prepared to investigate the electrocatalytic oxidation of malachite green (MG). The comprehensively analyzed XRD and XPS results confirmed that the partial incorporation of Y2O3 nanoparticles reduced the crystal size of PbO2 and increased the adsorption of hydroxyl oxygen (Oads). The bipotential step chronoamperometry (BSCP) curve suggested that PbO2/Y2O3 anode possessed larger diffusion coefficients (D) and catalytic rate constants (Kcat). In addition, the incorporated Y2O3 nanoparticles promoted the electrocatalytic activity at the anode interface and enhanced the electron transfer as well as accelerated the generation of reactive oxygen species (ROS), which afford the PbO2/Y2O3 anode high removal efficiency of MG and total organic carbon (TOC) with low energy consumption under the optimum conditions. Moreover, the electrocatalytic degradation mechanism and possible electrocatalytic mineralization pathway of MG on PbO2/Y2O3 anode were also discussed in detail, which provides a reference for the material science and environmental governance in the future.