The work aims to prove that the research on the surface properties of powdery rust of bronze relics has an important significance on building reasonable and effective protection methods as the powdery rust will cause serious damage to bronze relics. Through self-assembly technology, the 3-mercaptopropyl trimethoxysilane (MPTS) and n-octyltriethoxysilane (OS) composite film on the surface of bronze test piece contaminated with powdery rust was prepared. The Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle meter were used to characterize and analyze the surface morphology and structure features of composite film. And the electrochemical test was carried out to study the corrosion resistance of test piece. FTIR and SEM showed that the silane composite film was well formed on the powdery rust surface of the test piece. After self-assembled, the surface of test piece was super-hydrophobic, and the contact angle was increased from 86.3° to 155.2°. About 91.3% of the contact area between the water droplet and the test piece surface was the liquid/gas interface. Only a small part of liquid was in contact with the test piece. The anti-corrosion property of self-assembled test piece was greatly improved. The self-corrosion current density Jcorr of test piece was reduced from 2.58×10?2 mA/cm2 to 1.081×10?3 mA/cm2, and the corrosion inhibition efficiency reached 95.81%. The silane composite film could form a protective film on the powdery rust surface of the test piece, so as to isolate the contact between the test piece and the liquid effectively, thus making it super hydrophobic, and improving its corrosion resistance.