The work aims to further improve corrosion resistance of conventional silane films on AZ91D magnesium alloy. The γ-aminopropyltriethoxysilane solution were doped with 0.50 g/L cerium nitrate to prepare cerium salt-doped silane films on AZ91D magnesium alloy by simple chemical immersion treatment. Surface morphology of the silane films before and after being doped with cerium salt was observed with scanning electron microscopy (SEM). Effects of cerium salt doping on corrosion resistance of the silane films in 5% NaCl solution were studied based upon open circuit potential-time curves, electrochemical impedance spectroscopy (EIS) and neutral salt spray test. Cerium salt-doped silane films were more smooth and uniform, thicker and denser than that of the conventional silane films. The magnesium alloy substrate was completely covered and no polishing scratch was seen. Stable potential of the cerium salt-doped silane films was about ?1.31 V, and it needed longer stabilization time. The cerium salt-doped silane films produced a larger low-frequency impedance value, thus effectively inhibiting the migration and diffusion of erosive particles toward the magnesium alloy substrate, and avoiding anodic dissolution of magnesium alloy substrate. By adding cerium nitrate to silane solution, the cerium salt-doped silane films could be prepared on AZ91D magnesium alloy. Corrosion resistance of the silane films was improved significantly because micro cracks and defects on the silane films were repaired to some extent by cerium ions.