Abstract: The tonsils of the pig were lymphoepithelial organs situated on the opening of both digestive and respiratory tracts. The morphology and ultramicrostructure of the various tonsils were studied on 15 pigs aged 5 months. The results showed that there were four tonsils in pig. The soft palatine tonsil and Paraepiglottic tonsil were both located on oropharynx tract. They consist mainly of secondary lymph nodules and were encapsulated in dense connective tissues. The stratified squamous epithelium covering the tonsils and their crypts was frequently infiltrated heavily by lymphocytes. The pharyngeal tonsil and tubal tonsil were situated on nasopharyngeal tract. The epithelium covering the tonsils was squamous epithelium that often distributes sparsely in some surface regions. The intercellular junction of the epithelium was looser, and the intercellular space was larger compared to other epithelium. These tonsils consist of scattered lymph nodules, aggregations of lymphocytes and diffuse lymphoid tissue. The feature of pharyngeal tonsil and tubal tonsil was benefit for the antigen absorption and presentation,and provide the sufficient evidence to intranasal immunization.