The purpose of this study was to evaluate the accuracy of the soft tissue profile predicted by Quick Ceph Image Pro in mandibular setback surgery. Preoperative and postoperative lateral cephalograms of 24 patients(9 males and 15 females) who had completed treatment that involved orthodontics and mandibular setback by BSSRO were used. Computerized cephalometric lines and video image predictions were generated and compared with the actual postoperative results. In horizontal measurement, predicted values were smaller than actual measurements. And lips were thicker than actual values. Most of the different between values and actual measurement were than 2mm, and it was clinically acceptable.