Objective　The purpose of this study was to provide an anatomical basis for prevention of post-irradiation xerostomia by submaxillary gland transposition in the submental region.　Methods　Under the portable operating microscope with 2.0~3.0 magnification, we dissected submandibular gland (SMG) and blood vessels of 30 specimens of normal adult head and neck through the external carotid artery with red latex and observed morphology of the submandibular gland, length of submandibular gland duct and course, distribution, adjacent relations,et al. of gland arteriovenous gland vessels.　Results　The submandibular gland was divided into two parts - shallow and deep , to the limit of posterior margin of mylohyoid muscle, the shallow part about (1.7±0.5) cm3 , the deep about（1.0±0.8）cm3  which was the extension for the submandibular gland. The submandibular gland ducts were from the submandibular gland deep issue, about 5 cm, opening in the sublingual caruncle on the side of the lingual frenulum.    Conclusion    This result is of reference value for prevention of post-irradiation xerostomia by submaxillary gland transposition in the submental region.