The work aims to study the effects of cerous sulfate on corrosion resistance of trivalent chromium passivation film. 0.3 g/L, 0.5 g/L, 0.8 g/L, 1.0 g/L and 1.5 g/L of cerium sulfate was added in trivalent chromium plating salt solution respectively. Then the corrosion current density of passivation film added with different addition volumes of cerous sulfate was compared through polarization curve test so as to determine optimal addition volume of cerous sulfate in the trivalent chromium plating salt solution. Later, trivalent chromium passivation films without cerous sulfate and with optimal addition volume of cerous sulfate were prepared respectively. Tafel polarization curve and electrochemical impedance spectroscopy (EIS) were measured by electrochemical workstation CHI660E. Electrochemical properties of the passive films were analyzed and the corrosion resistance of different passivation films was studied as well. The morphology of the passivation films with and without cerium sulfate cerium sulfate was compared. When the addition volume of cerous sulfate was 1.0 g/L, corrosion current density of the passivation film was less than that of passivation films with other volumes of cerous sulfate. Corrosion resistance of passivation film with cerous sulfate differed from those without cerous sulfate, and the former was provided with better performance and different morphology. Therefore, corrosion resistance of the trivalent chromium passivation film is improved when added with cerous sulfate. The corrosion current density is the minimum 3.835×10-6 A/cm2 and the corrosion performance is superior to that of other films when 1.0 g/L of cerous sulfate is added.