To evaluate the efficacy and safety of Smith-Petersen osteotomy (SPO) assisted by releasing disk space from posterior approach for thoracolumbar kyphosis. A review was conducted on 8 patients (3 males and 5 females) with thoracolumbar kyphosis were treated with SPO assisted by releasing disk space from posterior approach at Department of Orthopaedics, Peking University Third Hospital from June 2016 to September 2017. The age was 56.5 years (range:18-71 years). There were 3 cases of Scheuermanns kyphosis, 2 cases of degenerative kyphosis, 1 case of proximal junctional kyphosis (PJK) after lumbar surgery, and 2 cases of kyphosis after thoracolumbar laminectomy. The paired test was used for statistical analysis in thoracolumbar kyphosis angle, osteotomy segment kyphosis angle, sagittal vertical value (SVA), visual analogue score (VAS), Oswestry dysfunction index (ODI) before and after surgery. Statistical difference was confirmed with 0.05. Osteotomy level included 2 cases in T(11-12), 3 cases in T(12)-L(1), 3 cases in L(1-2.) The average operation time was 339 min (range: 247-416 min), bleeding volume was 1 275 ml (range: 500-2 500 ml). The mean follow-up time was 16.5 months (range: 12-24 months). The average thoracolumbar kyphosis angle was 59.9° (range: 40°-73°) pre-operation, 9.5°(range:-5.1°-20°) post-operation and 13.5°(range:-1.3°-28°) at the latest follow-up. It made an average correction with 46.4°and corrective rate with 78.0%. The osteotomy segment kyphosis angle was 37.9° (range: 26°-46°) pre-operation, -1.3° (range:-11°-13°) post-operation making an 39.2° open-up angle, and 2.0° (range:-13.5°-13°) at the latest follow-up. Lumbar lordosis was 47.5° (range: 2°-76°) pre-operation, 41.2°(range:15°-62°) post-operation and 36.9°(range:15°-58°) at the latest follow-up. SVA was 54 mm(range:-34 mm-149 mm) pre-operation and 39 mm(range:-3 mm-119 mm) at the latest follow-up. VAS score of low back pain was 6.3(range:0-9) pre-operation and 3.0(range:0-6) at the latest follow-up. ODI score was 21.9(range: 0-42) pre-operation and 11.0(range: 0-26) at latest follow-up. Comparing to pre-operation value, there were statistical difference in the thoracolumbar kyphosis angle( 8.547, 0.000), osteotomy segment kyphosis angle(9.739, 0.000), VAS(3.077, 0.018), ODI(5.800, 0.001) at the latest follow-up. There was no neuropathic complication in all patients. Cerebrospinal fluid leakage occurred in 2 cases with spinal surgery history, and recovered after symptomatic treatment. SPO assisted by releasing disk space from posterior approach could safely achieve effective correction of rigid thoracolumbar kyphosis deformity within 40°.