Recently, the treatment principles of congenital dislocation of the hip has been altered markedly. The importance of concentric reduction and its maintenance during growth period in CDH has been stressed by many authors. Acetabular remodelling capacity has been argued between many authors, because it was critical criteria about the determination of operating period and methods. Authors selected 25 cases of congenital dislocation of the hip, which was treated by closed reduction, open reduction and femoral osteotomy to obtain concentric reduction of the hip. And we analyzed the change of acetabular angle and femoral anteversion in two group: Group 1-below 2 years and Group 2-from 2 years to 4 years old. The results were as follows: 1. The change of acetabular angle was improved markedly: average 15° in the Group I and average 13° in the Group 2 in 2 years. 2. The change of femoral anteversion in the Group I was markedly improved: average 15°, but, the in the Group 2 was not significant: average 6°. 3. It was thought that the perfomance of femoral osteotomy without innominate osteotomy in the Group 2, could achieve the satisfactory acetabular remodelling.