Abstract: Organic additives play a crucial role in the production of electrolytic copper foil, as their concentration fluctuations directly affect the microstructure and properties of the foil. In this study, cyclic voltammetry stripping (CVS) was used to quantitatively analyze the concentration depletion in a combined additive system consisting of sodium 3-mercapto-1-propanesulfonate (MPS), polyethylene glycol (PEG), and collagen. This approach aimed to achieve effective regulation of the plating solution composition and stabilize copper foil performance. Experimental results showed that the MPS decreased from an initial 5.17 mg/L to 0.05 mg/L after continuous electrolysis of copper foil, while the concentrations of PEG and collagen changed slightly. According to the spiked recovery tests, the recovery rate of MPS ranged from 97.41% to 102.93% with a relative standard deviation of 1.23% to 5.47%. The large amount of MPS consumption led to a sharp increase in grain size to 7.49 μm, and surface roughness to 4.21 μm. Furthermore, it prompted the preferential growth of the (111) grain surface, resulting in a maximum tensile strength of 452.67 MPa and a minimum elongation of 0.67%. Based on CVS test results, the depleted MPS was replenished, restoring the copper foil to its initial properties: a grain size of 3.66 μm, a roughness of 1.05 μm, preferential orientation along the (111) and (200) planes, a tensile strength of 376.47 MPa, and an elongation of 2.38%.