Abstract: Oral mucosal drug delivery has the advantages of rapid drug absorption, no first-pass effect and good patient compliance. However, factors such as low drug dissolution, saliva carrying the drug into the gastrointestinal tract and the existence of physiological barriers in the mucosa may affect the mucosal permeation and bioavailability of the drug. Nanotechnology applied to drug oral mucosa delivery can overcome the above disadvantages and obtain efficient absorption effect. This paper describes the physiological structure of oral mucosa and the factors affecting the absorption of drugs in oral mucosa, reviews the application of nanotechnology such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, polymer nanoparticles, polymer micelles and nanohybrid suspensions in oral mucosal drug delivery and the mechanism of promoting drug absorption, summarizes the main problems of current research, and gives an outlook on the application of nano oral mucosal drug delivery system. The main problems of current research are summarized, and the prospects for the application of nano oral mucosal drug delivery systems are discussed.