Abstract: Passivation film performance on surface of S22053 stainless steel in 6wt% FeCl₃ solution was studied by methods such as anodic polarization, constant potential film formation polarization, electrochemical impedance spectroscopy and Mott-Schottky test. The results show that the film formation potential of S22053 stainless teel was between 0.3-0.9 V. The maximum module value of impedance increased with increasing film formation potential in the range of 0.3-0.8 V, indicating that the stability of the passivation film was enhanced; in the range of 0.8-0.9 V, the opposite was true. The passivation films, formed after polarization at different film formation potentials for 30 min, showed an n-type semiconductor characteristic in the scanning potential range of 0-0.6 V, and a p-type semiconductor characteristic in the range of 0.6-0.9 V. The change of the passivation film thickness with the film formation potential obtained by electrochemical impedance spectroscopy was consistent with the change of the space charge layer thickness with the film formation potential obtained by Mott-Schottky curves; both reached peak values at film formation potential of 0.8 V.