Objective To compare the values of cone beam CT (CBCT) with panoramic radiograph in preoperative planning for extraction of mandibular impacted wisdom teeth. Methods Totally 97 patients with 135 wisdom teeth were assessed with panoramic radiograph, and 41 cases presenting 52 impacted wisdom teeth underwent additional CBCT scan were enrolled in this study. Preoperative planning was made for removal of bone, decapitating the crown, sectioning the root and direction of tooth luxation according to the information provided by panoramic radiograph and CBCT images. The Results were processed statistically with SAS 9.3.1 software package for χ2 test. Results Compared with the panoramic radiograph, CBCT provided a more precise and quantitative guide for bone removal, root sectioning and direction of tooth luxation (P＜0.001). The two Methods showed no significant difference in making decision of crown decapitating. Conclusion CBCT can provide comprehensive three-dimensional information during preoperative planning for the extraction of mandibular impacted wisdom teeth. An appropriate surgical approach, with correct tactics and Methods may facilitate the operation, prevent impairment to adjacent structures and reduce surgical complications.