Developmental hip dysplasia is the most common deformity of the pediatric lower extremity. The etiology is unknown and it may be a multifactorial disease with risk factors including: girl, hormones, genetic factors and intrauterine factors (breech position, low amniotic fluid, first birth, high birth weight, extended knee position) and postnatal position. The incidence of developmental hip dysplasia varies between geographic regions and races, with a prevalence of 1% to 4% in China. Early diagnosis and treatment can achieve up to 80% of normal development through closed repositioning. The goal of treatment is to achieve and maintain hip repositioning to provide an optimal environment for hip growth and development. The early diagnosis and treatment of congenital hip dislocation is very important; treatment is relatively simple for babies under 6 months of age; for babies 3-6 months of age, both lower limbs can be reset by maintaining a high degree of external booth, and can be fixed with Pavlik slings and frog splints; more than 95% can be cured after 3 months; this treatment method does not damage the joint and has few complications; for babies who start walking at around l years of age, the dislocated joint needs to be repaired first. Children above 3 years old have a high failure rate of manual repositioning, and children between 4 and 7 years old need to be repositioned by surgical incision. The younger the baby is, the better the result; the older the baby is, the more traumatic the surgery and the worse the result. If hip dislocation is left untreated, it will lead to leg disability, walking lameness, and when they grow up, their legs cannot be stressed and they will feel sore and painful when walking.