Developmental Dysplasia of the Hip (DDH) is one of the most common osteoarticular deformities, which refers to the abnormal correspondence between the femoral head and acetabulum, including bony, cartilaginous, and soft tissue structure and morphology. The current basic view on DDH is that if diagnosed and treated early, most cases can be completely restored to a normal hip joint; if the diagnosis and treatment are delayed, the normal development of the hip joint will be affected, and even with complex surgical treatment, it is difficult to restore the normal structure, form and function of the hip joint, which not only affects the growth and development of children and adolescents, but also makes the patient’s hip joint in adulthood possible This not only affects the growth and development of the hip joint during childhood and adolescence, but also makes it possible for patients to develop osteoarthritis in the hip joint at an early age, which affects their quality of life. Imaging is an important method for the diagnosis of DDH, which used to be based on the principle of X-ray, relying mainly on the assessment of ossified structures to determine the normalcy of the hip joint. the advent of ultrasonography of the hip joint in the late 1970s made it possible to assess cartilage and soft tissue structures that are difficult to show on X-ray, and has significant advantages. The new examination technique is playing an increasingly important role in the early diagnosis and treatment of DDH, and many large and even medium-sized cities in China are including this technique as an element of neonatal examination, and more and more cases of DDH are being diagnosed at an early stage.