[abstract]objective to investigate the sonography value of the clinical diagnosis of developmental dysplasia of the hip(DDH) in infant by Graf method.methods 925 cases of infant within 6 months of age in our hospital who recieved high-frequency sonography diagnosis first time between January 2014 and June 2017 were collected, the shape of acetabular and the match of femoral head and acetabular were observed,α and β angle were measured and classified by Graf medthod.Result the bilateral hips of 925 cases of infant were checked.of these,352 cases were male, and the other 573 cases were female,1850 cases of hip-joint were included.Graf sonography diagnostic typing result was 1456 cases type I (normal,78.7%),198 hips type IIa(less mature,10.7%),132 hips type IIb (dysplasia,7.4%),39 cases type IIc(dysplasia,2.11%),3 cases type D(decentered joint,0.16%),22 cases type III/IV(dislocated,1.19%).Conclusion hip sonography by Graf method is safe and convenient,with high screening rate of dysplasia which would lead to dislocation but can not be easily found by clinical body examination.Therefore,it is important to early screen and diagnose of DDH.