The surface silanization was carried out on ultrasonic micro-arc oxidation(UMAO) coatings on pure magnesium using KH550 as silane coupling agent(SCA). The surface morphology, chemical bonds and corrosion resistance of the silane films were investigated by scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FTIR) and electrochemical workstation, respectively. The results showed that hybrid coatings were successfully prepared on pure magnesium by UMAO-Na OH(1 mol/L, 2 mol/L, 3 mol/L)-SCA processing. The organic films with Si–O–Mg bonds are helpful for the reduction of the pores in UMAO coatings. The pores decreased with increasing Na OH concentration. Compared with single UMAO treatment, the corrosion potentials(Ecorr) of magnesium plates with UMAO-Na OH(1 mol/L,2 mol/L, 3 mol/L)-SCA treatment increased by 29 m V, 53 m V and 75 m V, respectively, meanwhile the corrosion current density(Icorr) reduced one to two orders of magnitude. It indicated that the corrosion resistance of the coatings was improved by silane treatment. The surface silanization was carried out on ultrasonic micro-arc oxidation (UMAO) coatings on pure magnesium using KH550 as silane coupling agent (SCA). The surface morphology, chemical bonds and corrosion resistance of the silane films were investigated by scanning electron microscope ), Fourier transform infrared spectroscopy (FTIR) and electrochemical workstation, respectively. The results showed that hybrid coatings were successfully prepared on pure magnesium by UMAO-Na OH (1 mol / L, 2 mol / L, 3 mol / L) The organic films with Si-O-Mg bonds are helpful for the reduction of the pores in UMAO coatings. Compared to single UMAO treatments, the corrosion potentials (Ecorr) of magnesium plates with UMAO (1 mol / L, 2 mol / L, 3 mol / L) -SCA treatment increased by 29 mV, 53 mV and 75 mV, respectively, while, meanwhile the current current density (Icorr) reduced one to two orders of magnitude. It indicates that the corrosi on resistance of the coatings was improved by silane treatment.