Abstract: Objective: The course of mandibular nerve canal in mandibular posterior region was judged by MSCT, which provided theoretical support for preoperative evaluation of mandibular posterior region implantation. Methods: MSCT data of 60 adult mandibles were collected to measure the distance of mandibular neural tube from the surrounding bone wall in the posterior tooth area and to compare and analyze the difference between male and female and between left and right sides. Results: The vertical distance from the upper margin of mandibular neural tube to the alveolar crest of mandible ranged from (13.21±1.73) mm to (18.03±1.73) mm, Except for the mental foramen area, there was statistical difference in gender, and no statistical difference between the left and right side. The vertical distance from the inferior margin of the mandibular canal to the inferior margin of the mandible ranged from (15.57±1.51) mm to (8.41±1.35) mm. There was statistical difference in genderand no statistical difference between the left and right side. The horizontal distance from the lateral margin of the mandibular canal to the buccal bone plate of the mandible ranged from 0 mm to (8.01±1.33) mm. The mean distance from the medial margin of the mandibular canal to the lingual bone plate ranged from (7.91±1.03) mm to (2.52±0.49) mm. There was no statistical difference in gender or left and right. Conclusion: MSCT can accurately reflect the course of mandibular canal; When implanting in the posterior mandibular region, the length of the implant is between 10 and 15 mm, which is relatively safe.