Ultra-thin alkali aluminosilicate glass produced by the float process was taken as the research object. Considering that the warping after chemical tempering might be caused by the fact that the surface compressive stress (FCS) multiply by depth of stress layer (dDoL) of the atmosphere surface was larger than that of the tin surface, a method of coating on the air surface of the glass was adopted to reduce the ion exchange degree of the atmosphere surface during chemical strengthening and narrow the difference of FCS×dDoL on both sides of the glass. By exploring the effect of different coating solutions on toughened warping, it was found that the tetraethyl orthosilicate (TEOS) coating system had a significant effect. The glass samples of 26.4 cm×19.8 cm×0.7 mm were chemical strengthened at 400 ℃ for 4 hours, and the average warpage value was reduced by 27%. The apparent quality of the coated glass met the subsequent requirements, providing an effective way to reduce the toughened warping problem in ultra-thin glass production.