本文利用三维Ｘ线头影测量系统对５０名恒牙早期的安氏Ⅱ类１分类错进行了研究，发现此类错的发病机制错综复杂，其颅面结构在长宽高三个方面都存在有不同程度的异常，本文对其进行了深入的探讨，并结合其颅面三维结构特点，将此类错进行了分型，提出了各自的治疗原则 In this paper, the use of three-dimensional X-cephalometry system of 50 permanent teeth early Class Ⅱ Division 1 malocclusions were found, and found that the pathogenesis of such misdiagnosis complex, the craniofacial structure in the length and breadth of the existence of three aspects Different degrees of abnormalities, this article has carried on the thorough discussion to it, and combined with its craniofacial three-dimensional structure characteristic, has carried on the classification to this kind of mistakes, put forward the respective treatment principle