To improve the corrosion resistance of 20^# steel，TiO₂-SiO₂ coating were prepared on the surface of 20^# steel by sol-gel method in this paper. The influence of Ti-Si molar ratio in sol on the preparation and corrosion resistance of the coating was studied. The surface microstructure of the coating was observed using laser confocal microscopy andscanning electron microscopy，the crystal structure was characterized by X-ray diffraction，the surface chemical composition was measured using an energy spectrometer，and the degradationeffect of the coating on methylene blue was studied through UV-visible absorption spectroscopy. The results showed that the Ti-Si molar ratio in sol had a significant impact onthe surface wettability，organic matter degradation，and corrosion resistance of 20^# steel. With the increase of SiO₂ content in the TiO₂-SiO₂ coating，the material turned from hydrophilicity to hydrophobicity，and its corrosion resistance was greatly improved. The optimal corrosion resistancewas obtained when the Ti-Si molar ratio was 1∶1. After an immersion in a 3. 5%NaCl solution for 48h，the 20^# steel sample coated with TiO₂-SiO₂ film was not corroded and almost maintained the original morphology.