Objectives: To determine and analyze the incisal jaw morphology ofmaxillary bone of class II division l malocclusion among different verticalskeletal facial types.　　 Materials and methods: 121 subjects of pretreatment lateralcephalometric radiographs with class II division l malocclusion including54 males and 67 females ofearly permanent dentition aged from 12-14 yearswere studied. SN-MP angle was used to select 59 average angle, 30 highangle and 32 low angle vertical skeletal facial types Chinese patients. Toobserve the incisal jaw morphology of maxilla and mandible much indexwere traced from lateral cephalograms were analyzed and measured usingfactorial analysis. 53 parameters including linear, area ratio and angularmeasurements were processed using t-test and ANOVA. The characteristicsof abnormal jaw morphology at incisor area of upper and lower incisorsamong three vertical facial skeletal types were discussed in detail.　　 Results: At the upper and lower central incisors low angle individualspresented a greater dentoalveolar and basal bone thickness than high andaverage angle individuals. The distance from the root apex of upper andlower central incisors were far away from the lingual cortex in low anglethan high angle individuals. The region between point PA, PC and TB, TCmay be regarded as the limitations of palatal and lingual movement ofmaxillary and mandibular incisors. The compensation inclined changes onthe palatal cortical plates relating to SN and PP plane and lingual corticalplates relating to GoGn plane brings compensation changes in themorphological structure of maxillary and mandibular jaws at incisor area inanterioposterior dimension. The areas of maxillary and mandibular basalbones showed consistent because of the inverted compensation changes inthe height and thickness of the incisor jaw bones. The ability ofcompensation changes may be stronger in maxillary jaw at incisor area thanmandibular jaw at the incisor area. The incisors and alveolar bone ofmaxillary and mandibular incisors inclined more labially in low angle thanhigh and average angle individuals.　　 Conclusion: Among different vertical facial types with class II division1 malocclusion in early permanent dentition may accord to establishdiscriminate values as a sample to set up the cephalometric standard for theappropriate diagnosis to provide better treatment plan for the clinicians.The result of this study has provided the evidence that morphology of thejaws in certain vertical facial types is not exclusive since, class II divisionlmalocclusion phenotype characterized by both abnormalities in both skeletaland dentoalveolar process，based in vertical facial types only we cannotanalyze the morphology of the incisal jaw bones. Discriminate diagnosismust be emphasized on clinical works.