The works aims to introduce rare-earth element Er to modify the intermediate layer SnO2-Sb2O3 and improve the binding force between the substrate and the active layer. PPy (polypyrrole) is added to the active layer of RuO2 to enhance the electrocatalytic oxidation performance of the electrode. SnO2-Sb2O3-Er as intermediate layer and RuO2-PPy active layer were prepared by coating thermal decomposition and electrodeposition with Ti as the matrix. The effects of Er and C4H5N concentration on the crystal phase structure were investigated by X-ray diffraction (XRD) and the scanning electron microscope (SEM), energy spectrum analysis (EDS) and infrared light (FT-IR) were used to analyze the morphology, element composition and phase structure of the intermediate and active layers. The oxygen potential and stability of the electrodes were tested by linear polarization (LSV) and electrochemical impedance testing (EIS) and accelerated life test. The electrolytic technology of composite electrodes was used to treat the waste water from shale gas and the ability to degrade organic matter was investigated. When n(Sn4+):n(Er3+) = 100:4, the grain size of the coating was the smallest, and the surface crack of intermediate layer doped with Er decreased relative to the intermediate layer undoped with Er. Thus, the passivation of the electrode could be prevented further. The PPy could effectively modify the active layer. After PPy was added, the oxygen evolution potential of the composite RuO2 electrode could be increased from 1.6 V to 1.8 V, the electrode resistance was reduced from 56.2 Ω to 7.6 Ω, the life of the electrode was extended from 267 days to 391 days and the COD removal rate of reflow wastewater could reach 93.7%. The addition of Er and PPy can improve the electrocatalytic activity of the electrode, and the degradation effect of organic matter in the wastewater is remarkable.