Compound silane films were prepared on galvanized steel by immersing method using mixture of bis-[3-(triethoxysilyl)propyl]tetrasulfide and γ-aminopropyltriethoxysilane. The corrosion resistance of galvanized steel substrates was compared after treatment with bis-[3-(triethoxysilyl)propyl]tetrasulfide, γ-aminopropyltriethoxysilane and their mixture in 3.5%NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy. The results indicated that corrosion current density of the mixed silane films was reduced evidently and self-corrosion pressure of that was shifted to left markedly and total impedance value of that increased about two orders of magnitude. The analytical characterisation was performed by Fourier transform infrared spectroscopy and atomic force microscopy. The results showed that bis-[3-(triethoxysilyl)propyl]tetrasulfide and γ-aminopropyltriethoxysilane were all connected with the former of films.