The stainless steel water cup used in daily life is easy to react with a variety of chemical components contained in water such as tea to precipitate heavy metals in stainless steel. The glass coating has good stability and corrosion resistance, which is widely used in many fields. Using tetraethyl orthosilicate as raw material, SiO2 inorganic coating was prepared on the inner surface of stainless steel thermos cup by sol-gel method. Compared with the samples without coating, the effect of coating on the precipitation of heavy metals was studied. The morphology of the coating surface was observed by electron microscope, and the adhesion of the coating was tested. Results show that the coating has an obvious effect on reducing the precipitation of heavy metals lead and cadmium. The coating has uniform particle distribution and good adhesion.