Objective:To discuss the fault ratio of transpedicle screw fixation in the thoracolumbar ,and analysis the causation and clinical treatments of it. Methods:From 2008 to 2010,total 262 cases that had thoracolumbar disease were treated with 1 207 pedicle screws fixation. The CT and X-ray features of 262 postoperative transpedicle screws placement were analyzed retrospectively, including the screw position, angle and cortical injury. And according to the distance of the screw thread perforated pedical cortical bone, the cortical injuries were divided into four degree,namely Ⅰ 0~2 mm, Ⅱ 2~4 mm,Ⅲ 4~6 mm,Ⅳ 6~8 mm. Results:Of all the pedicle srews,CT and X-ray showed that the pedicle cortical bones were often injured by the screw thread. There were 41 (3.40% )screws perforating the cervical pedicle,24 withⅠ, 12 with Ⅱ,5 with Ⅲ, and 3 with nerve root injury(1.15%). Conclusion:Although pedicles of thoracolumbar are narrow, many faults of transpedicle screw fixation of thoracolumbar can be avoided, if we read images clearly before operations, use radiation to locate, probe to check screw channel and choose. suitable screws.