It has been reported in our previous works on liquid phase deposition (LPD) method that uniform, dense and pure silica film could be deposited from supersaturated hexafluorosilicic acid aqueous solution at near room temperature. According to our recent work, it was found that silica film could be deposited even on several kinds of polar plastics by optimizing the pre-treatment condition. Further work revealed that non-polar plastics such as cycloolefin polymer could be coated by the LPD method. The adhesion of the deposited silica with the plastic substrates was good enough at the initial stage and even after the durability test. Several merits over ordinal coating methods are considered for this silica film on plastics and many applications such as optical lens, liquid crystal display devices are proposed here.