the present disclosure relates to the field of preparing an inorganic nanometer material and application thereof , and specifically relates to a film - forming silica sol , a method of preparing the silica sol , and usage thereof . the present disclosure provides a film - forming silica sol comprising , by weight percentage , constituents of : silica sol : 66 - 91 %; modifying agent : 0 . 1 - 1 . 8 %; film - forming auxiliary : 7 . 2 - 33 . 9 %. the present disclosure further provides a method of preparing a film - forming silica sol and an application thereof . with the film - forming silica sol , a method of preparing the silica sol , and usage thereof according to the present disclosure , the prepared film - forming silica sol has a good appearance transparency and stability , and when applied to paint as a film - forming coating , it has a good glossiness , a high hardness , and a strong adhesive force ; therefore , it has a high practical value in the paint field .