Objective:To explore the key point of microsurgical treatment of ventral malformation of craniocervical junction and discuss the anatomic foundation of microsurgical methods. Methods:The anatomy structures were observed and measured in 15 cadveric heads. The clinical data of 16 consecutive patients with ventral malformation of craniocervical junction operated upon through transoral approach,from September 2003 to June 2007,were reviewed retrospectively. Results:The operative exposure in transoral approach ranged from lower clivus to the superior part of the C3 vertebral body. The distance from the vertebral artery to the midline:20.1 mm at the level of C12,16.2 mm at the level of C23. Among the 16 patients,there was good recovery in 11,improvement in 4,and no changes in 1. The complications included cerebral-spinal fluid leakage in 1 case and severe swell of the tongue in 1 case. There was no operative mortality in call cases. Conclusion:Transoral mirosurgical decompression is the first selection of treatment for ventral malformation of craniocervical junction,with short distance, alleviative operative trauma and few complications.