The aim of this study was to investigate the feasibility and clinical efficacy of treatment of adolescent idiopathic scoliosis of >100° via posterior-only surgery with strong halo-femoral traction and posterior wide release. From December 2003 to August 2006, 121 patients with adolescent idiopathic scoliosis were treated in our hospital; among them, 29 patients with curves over 100° were included in this study. From December 2003 to June 2005, group A included the first 12 patients who underwent combined anterior release followed by two-week halo-femoral traction and then posterior instrumentation. From July 2005 to August 2006, 17 patients in group B underwent posterior surgery alone with strong halo-femoral traction and posterior wide release. All of the patients were followed-up for a minimum of 31 months (mean, 36 months; range, 31–41 months). There were no severe complications. All of the patients achieved bony fusion without instrumentation breakage or pseudarthrosis. There were no statistically significant differences between the two groups in gender, age, type of adolescent idiopathic scoliosis, preoperative coronal major curve values, major curve flexibility, or final follow-up major curve correction rate. The average operative time, blood loss and hospital stay in group B were less than those in group A. In adolescent idiopathic scoliosis with Cobb >100°, posterior-only surgery with strong halo-femoral traction and posterior wide release can provide comparable curve correction with shorter operative time, less blood loss and shorter hospital stay when compared to combined anteroposterior surgery.