2024-T6 Al alloy sheet s were modified by bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) silane film to improve the corrosion resistance. Fourier-Transform Reflection Absorption (FTIR-RA) spectroscopy was used for structural characterization of BTESPT silane film formed on surface of the sheet. Potentiodynamic polarization and immersion test in 3.5% NaCl solution were used for evaluating the corrosion performances of the silane film. The results showed that the film formed after curing at 120 °C for 40 min was cross-linked through Si-O-Si and that it was covered on the entire surface of the sheet. The content of elements S and Si on the Al2CuMg particles is a little higher that of on the matrix. The strong peak at 1032 cm-1 indicated that the film was linked to the sheet by Si-O-Al. Compared to the untreated case, the corrosion current density of the sheet treated with the silane film was reduced by close to 2 orders. Treatment of BTESPT silane can provide about 670 h protection of corrosion for the sheet in 3.5% NaCl water solution.