Electrochemical oscillation (EO) system with many kinds of coupling processes is normally accompanied by rich nonlinear dynamic mechanism. The electrochemical potential oscillation on quaternary alloy anode in electrolytic metal manganese (EMM) with and without sodium oleate (NaOL) was studied to investigate electrode reaction process. It is observed that NaOL affected the amplitude and frequency of potential oscillation by chronoamperometry measurement and phase space reconstruction. Furthermore, the linear sweep voltammetry (LSV) results revealed a certain amount of NaOL could reduce the overpotential of oxygen evolution reaction (OER) on the anode. In electrochemical impedance spectroscopy (EIS) exploration, the electrode process presented different reaction mechanisms in the absence and presence of NaOL. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were utilized to characterize the obtained electrolytic product. The combination of OL− and Mn2+, to a certain extent, inhibited the side reaction on anode, responded with reduced potential oscillation frequency and decreased potential value in phase space portrait. Based on the gained results, the relationship between EO and electrode reaction mechanism regulated by NaOL in EMM was proposed. This makes it possible to regulate electrochemical reaction by adjusting the intuitive oscillating signals.