The conversion coating containing trivalent chromium was prepared on the surface of 2A96 Al alloy by adjusting the solution of different concentration of Cr2(SO4)3 and K2ZrF6. The electrochemical corrosion properties of the conversion coating containing chromium trivalent were studied by polarization curves and AC impedance spectroscopy. The surface morphology of aluminum alloy before and after coating formation was observed by metallographic microscope and scanning electron microscope (SEM). The results showed that in the single-factor test, the self-corrosion potential of the conversion coating containing trivalent chromium was the highest when the mass concentration was 5 g/L Cr2(SO4)3 and 2.0 g/L K2ZrF6 solution, the maximum phase angle of the AC impedance spectrum was the highest, while the impedance arc length was the largest, and the corrosion resistance of the conversion coating containing trivalent chromium was the best. The results of the microstructure analysis indicated that the surface of 2A96 aluminum alloy was covered with a conversion coating after the conversion test.