Objective: To retrospectively study the skeletal stability of the skeletal Class Ⅱ malocclusion patients who has had bimaxillary orthognathic surgery at Peking University School of Stomatology in the past 10 years.Materials and Methods: 60 skeletal Class Ⅱ malocclusion patients, who had received bimaxillary orthognatic surgery,were included in our study.All patients were high angle patients and had BSSRO to advance the mandible.Lateral cephalometric photographs were taken before operation, immediately after operation, 3, 6, and 12 months after operation.The stability of skeletal landmarks and dental relationships was examined.Statistic analysis was performed to analyze the data.