Film-forming gel drug delivery systems are novel pharmaceutical dosage forms that present a gel form during preparation and storage and form a smooth and flexible solid film with hydrophobic and bioadhesive characteristics within 30 to 60 seconds after administration, which provides some superior advantages for topical application compared with traditional gel, spray and ointment preparations.Upon administration to buccal mucosa or dermal surface, the water-proof bioadhesive film formed can be retained at the application site for 5 to 12 hours without interference to daily activities and provide a sustained drug release, which is quite convenient for treatment of oral ulcer and skin disease.