Clinical manifestations: Younger children within 1 year of age: asymmetrical hip pattern bilaterally, popping of the hip joint during urinary and faecal care, shortening of the lower limb on the affected side. older children over 1 year of age: lameness is often the main reason for pediatric visits, manifested as lameness when one hip is dislocated, and bilateral dislocation manifested as “duck stance”, ” uplifted abdomen” and pronounced posterior hip. Hazards: If DDH is not treated in time, the deformity of the skeleton and soft tissues of the child will increase with age, and even secondary pelvic tilt and scoliosis will occur, resulting in permanent disability for the child. Treatment: At present, our department usually adopts Pavlic sling treatment for children less than 6 months old; less than 1.5 years old adopts conservative treatment, i.e. closed repositioning combined with plaster and brace treatment; 1.5 to 2 years old adopts individualized treatment plan, and the treatment plan is decided according to the specific condition; children older than 2 years old adopts “incision and repositioning + Salter pelvic osteotomy + femur For children older than 2 years old, the latest international procedure of “incisional repositioning + Salter pelvic osteotomy + proximal rotation shortening inversion osteotomy + angular plate fixation” was adopted, and good treatment results were achieved. Prognosis: In general, after systematic and correct treatment, the cure rate can reach more than 90% before the age of 1 year, while 2/3 of children who undergo conservative treatment after the age of 1.5 years may have residual deformity. The treatment can either be conservative or surgical after the age of 2 years. Generally speaking, children between the ages of 2 and 5 years old have good surgical results, and most of them can return to normal or close to normal; children between the ages of 6 and 8 years old have relatively poor treatment results, but they can also achieve better results; children after the age of 8 years old should be treated or not depending on the specific situation, and generally speaking, surgery should be done carefully for bilateral onset, and surgery should be done as much as possible to restore the concentric circle of the head socket for unilateral onset, even if the function is not good. In general, surgery should be performed cautiously in bilateral cases, and in unilateral cases, surgery should be performed to restore the concentric circle of the cephalic socket as much as possible.