Objective To review our experience on correction of low grade and medium congenital scoliosis by posterior spinal fusion. Method During 1978～ 1998, 56 patients with low grade and medium congenital scoliosis were treated by posterior spinal fusion with autologous bone、 xenogenic bone and recombining xenogenic bone in our department. Preoperative Cobb angles of all patients were less than 40 degrees. Result The study covered 50 patients with minimum follow up period from surgery of 2 years ( mean 9.5 years, ranging from 2～ 22 years ). All patients have got satisfactory fusion, and the Cobb angels of all patients after operation have no increase with the increase of age. Conclusion Posterior spinal fusion in treatment of low grade and medium congenital scoliosis is easy to do, safe and less injury and cost. The follow up results are satisfying. It is necessary and important to use orthosis and doing orthopedic exercise to consolidate and improve the curative effect after operation. rnrn