The surface morphology, element composition and corrosion resistance of potassium fluoferrite conversion coating after fluosilicate sealing were tested by scanning electron microscope, energy-dispersive spectroscopy, electrochemical test and neutral salt spray test . The results show that the sealing of SiO₂colloid from potassium fluosilicate hydrolysis on potassium fluoferrite conversion coating make steel corrosion current density decrease and anti-corrosion performance increase.