The work aims to study the invaliding laws and corrosion resistance of waterborne epoxy/silanated nano-TiO2 composite protective coating in 3.5%wt sodium chloride solution. The surface of the nano-TiO2 particles was chemically grafted with 3-aminopropyltriethoxysilane (APTES) and uniformly dispersed in a waterborne epoxy coating. The mixed coating was coated on a Q235 steel sample. The chemical grafting modified behavior on the surface of nano-TiO2 was investigated by Fourier transform infrared spectroscopy (FTIR) and thermo gravimetric analyzer (TGA). The electrochemical performance of the composite coating was tested by electrochemical workstation. The morphology of the composite coating was observed by laser confocal microscopy. The chemical grafted structure of nano-TiO2 modified by 10wt% APTES was mainly the single-tooth spiral structure; while the nano-TiO2 modified by 20wt% APTES had the highest grafting density of 11.78 APTES/nm2. The electrochemical test results showed that the epoxy/TiO2 composite coating had better corrosion resistance than the pure epoxy coating and the epoxy/TiO2 composite coating obtained by modifying nano-TiO2 with 20wt% APTES provided the best protection for the substrate, because the coating resistance was 12 times that of the pure epoxy coating, and the charge transfer resistance was 18 times that of the pure epoxy coating. Under the same corrosion conditions, the single-tooth spiral structure was more easily destroyed. The addition of silaneted nano-TiO2 particles could significantly reduce the peaks and holes in the coating surface. The grafting density of APTES molecular on nano-TiO2 particles is the direct factor to improve the corrosion resistance of waterborne epoxy/silanated nano-TiO2 composite protective coating.