A mathematical model for the separation of oveflapping voltammetry-peaks is presented. In this model, the general equation which was derived from the peak-current formulas of various polarographic (or voltammetric) methods, was combined with the revised Gussian function and capacitance-current function as a fitting function of polarographic eurrent peak. By the non-linear least square method using microcomputer, the parameters such as peak-current, peak-potential and width of wave can be accurately obtained individually. The experimental verifications were carried out by differential pulse polarography and alternating current polarography in various systems with the ions of In, Cd, Cu, and Pb. The results obtained by fitting single peak and separation of overlapping peaks showed that the mathematical model is very well suited to the practical polarographic processes, the fitring function based on the presented mathematical model is rational and reliable, and has an excellent precision for the separation of the overlapping voltammetry-peaks.