A study of 10 cadavers and 100 CT scans of lumbar spine was performed to investigate the topographical anatomy of the posterolateral disc puncture in percutaneous lumbar discectomy.A way of the puncture at L_5-S_1 disc,with comparative plain films of lumbar spine in different positions were taken in 50 cases.The results showed that the pos- terolateral approach for percutaneous discectony was a safe way.However,it is important to have full knowledge of the regional topographical anatomy associated with the puncture tech- nique to avoid the potential neurovascular complications.The special position designed by authors for the puncture at L_5-S_1 disc is useful by lowering the position of iliac crest which hinders the entrance of needle,thus can raise the successful rate of the percutaneous discec- tomy 100% successful rate of the disc puncture at L_5-S_1 disc was obtained in 130 cases.The two puncture parameters of Chinese associated with percutaneous lumbar discectomy were first measured;and also the route including nearby structures,the complications were dis- cussed.