In electroosmosis, interfacial resistance has a significant impact on system energy consumption and drainage efficiency, with electrochemical factors being particularly crucial. Although existing studies have analyzed this through empirical or theoretical models, most of these models lack objective electrochemical evidence. The fundamental reason for this limitation lies in the absence of operando monitoring techniques capable of intuitively capturing the electrochemical characteristics of interfaces. Based on this, this paper relies on the principle of linear sweep voltammetry (LSV) and independently develops an electrochemical operando monitoring device suitable for electroosmotic interfaces. By applying a linear potential scan to obtain polarization curves (i.e., curves representing the variation of interfacial current with potential), the electrochemical behavior of the interface is visually characterized. To compare and analyze the electrochemical response characteristics of different electrodes, copper, iron, and aluminum electrodes are selected in this paper. The results indicate significant differences in the polarization curves of different electrodes. These curves can be divided into linear and nonlinear types according to their morphology, corresponding to the dominant effects of ohmic resistance and activation resistance, respectively. Based on this, this paper proposes two types of interfacial resistance models: linear and nonlinear, and verifies their applicability under different electrode and soil conditions. The nonlinear model comprehensively considers various electrochemical factors and is suitable for characterizing the variation of interfacial resistance under complex conditions. When the polarization curve exhibits linear characteristics, the simplified linear model neglecting activation resistance can still maintain high fitting accuracy. In summary, this paper constructs a unified research framework for electrochemical operando monitoring and interfacial resistance modeling, providing new theoretical basis and technical support for revealing the electrochemical mechanism of soil-electrode interfaces and optimizing electroosmotic energy consumption.