Objective:　To　study　the　law　of　shape　changes　of　mandiblular　distraction　osteogenesis　in　the　patient　with　hemifacial　microsomia(HFM)　and　compare　the　results　with　the　real　effect　on　the　patient　by　establishing　the　models　of　mandibular　and　masticatory　muscles,　and　to　put　forward　some　good　suggestions　on　procedures　of　treating　patients　diagnosed　as　HFM　and　related　cases.　Methods:　Based　on　the　original　data　of　the　patient　with　HFM,　combined　with　the　MIMICS　software　(medical　image　control　system　software),　the　model　of　the　patient＇s　mandibular　and　masticatory　muscles　was　constructed　by　applying　the　technique　of　three　dimensional　(3D)　reconstruction,　and　then　put　the　entity　structure　into　the　ANSYS　software　to　simulate　the　effect　of　the　surgery.　Results:　The　established　preoperative　and　postoperative　finite　element　analytic　model　could　present　the　characteristics　such　as　digitalization　and　individuation.　Conclusions:　Compared　with　the　effects　of　the　real　surgery　for　the　same　patient,　the　result　of　numerical　simulation　showed　to　be　good　matching　and　could　provide　personalized　guidance　for　different　patients　before　their　operation.