Objective　To investigate anatomic features of the mandibular canal under spiral CT and panoramic radiography.　Methods　Mandibles of healthy young volunteers were continuously scanned transversally by spiral CT, and by panoramic radiography, respectively, followed by 3D reconstruction. The anatomic position of mandibular canal was measured and compared according to two kind of reconstructed images.　Results　At the buccal-lingual direction, mandibular canal inclinated gradually from lingual surface to buccal surface and reached mental foramen finally, which coursed through the third and second molars before reaching mental foramen. There were no anatomic difference could be identified between two kinds of skills（P＞0.05）.　Conclusions　Spiral CT scan supplied with panoramic radiography detection is reliable for guiding the alveolar operation.