〔Abstract〕 Objective To measure and analyze the position and shape of implant-related anatomical structure such as mental foramen, mental canal and the submandibular fossa in the adult mandibular posterior tooth area based on Cone Beam Computed Tomography(CBCT)images, and to detect the relationship between anatomical structures and the anatomice buccalingual angulation at implant site in order to help determine the implant angulation at the implant treatment-planning phase. Methods Random samples of 181 CBCT images were selected and analyzed, including 109 patients with dentition defect: 59 males and 50 females, and 72 patients with non dentition defect: 36 males and 36 females. The anatomic marks and alveolar bone inclination of mandibular posterior tooth area were measured respectively, and the results were statistically analyzed. Results The inclination angles of alveolar bonewere(5.08±3.86) on the left and(3.07±5.20) on the right of the mental foramen area,(8.57±5.03) and(9.54±5.19) on the first mandibular molar,(15.48±5.23) and(14.21±6.67) on the second mandibular molar, and the inclination angles of the left and right mental canal were(41.81±10.07) and(44.77±8.96) respectively. The distance from the upper edge of the mental foramen to the top of the alveolar ridge was(12.35±2.38) mm, and the distance between the mental canal at 1.5 mm inside the mental foramen and the top of the alveolar ridge was(14.14±2.46) mm. The depth of the submandibular gland fossa in the first and second molars were(0.80±0.56) mm and(1.00±0.50) mm, the distance from the most concave point to the alveolar crest top were(14.15±5.95) mm and(14.52±3.55) mm, the distance from the most convex point of the crown to the alveolar crest top were(10.71±4.72) mm and(9.25±2.81) mm, and the distance from the upper edge of the mandibular canal to the alveolar crest top were(15.52±3.48) mm and(13.83±2.76) mm. Conclusion The buccallingual inclination of mandibular alveolar bone is gradually inclined from buccal side to lingual side from premolar area to molar area, and the lingual inclination in the second molar area is the most obvious; The implant tip can stop at the upper edge of the mental foramen to obtain better initial stability; The existence of submandibular fossa limits the depth and direction of implant implantation to a certain extent. It is necessary to accurately measure and analyze this part with CBCT before operation to avoid complications such as mandibular lingual perforation and improve the success rate of implant repair.