objective: the simulating operation of contouring mandible was performed on the software platform and arrived at the individual schemes for osteotomy.Then,the operations of mandibles were carried out according to the schemes;methods: Simulatinging operation and clinic research.23 cases, with project mandible angles, were selected as research objects,all of which preoperative key indexes related to the mandibles were gained and simulating osteotomy of the shaping madibles based on the key indexes from good appearances were performed.All cases were undergone shaping operations as the simulating procedures by the oral approaches. Postoprative key indexes were gained by the 3-D CT. Pre-and postoperation data were statistically analysed and experts evaluated the appearances again;Results: The vital important indexes of the mandible were screened based on the coefficincy of variations and standard deviations：intermadible angle distance,ratio of ramus mandibulae to corpus mandibulae, mandibule angle value, etropion angle, value of mandible angle, mandibular plane angle，inferior margin angle of corpus mandibulae，chin project，ratio of middle to inferior face;The mandible shaping procedures were smooth. There were no statistically significant differences beween the pre-and postoperative key indexes related to mandibles。All cases were appraised after 6 months and results showed satisfied appearances in 20 cases, near to satisfied in 2 and unsatisfied in 1;conclusions: The shaping mandible operation based on the key indexes and simulating osteotomy may gain a good result.The preoperative procedures exhibited a guiding signifince and avoided blind osteotomy.