Objective To evaluate the efficacy of the shelf operation using a ilium segment atteched tensor fascia latae and the intertrochanteric osteotomy to cure the congenital dislocation of hip or hip dysplasia patients more than eight years;To establish normal value ranges of biomechanical indexes of normal adults and normal children. Methods Using Legel's mathematical model ,the standard pelvic X-rays of normal adults?normal children? hip displasia patients and postoperation was measured and calculated. Results 15 years′ fellow-up and the results of the mathematical analysis proved that the operation can improve the biomechanics of the patients' hip joints. The operation also accords with biomechanical principles. Conclusion Operateional method should be selected flexible according to the biomechanical principles and the patients conditions.