Pediatric hip dysplasia, also known as pediatric developmental hip dysplasia, is a relatively common disorder in pediatric musculoskeletal aspects. There are static and dynamic ultrasound assessment methods for pediatric hip dysplasia. The static assessment method requires observation based on the change of α angle and femoral head coverage. α angle is the angle made by the intersection of the top line of the bone and the baseline, which is used to measure the bony acetabular development; β angle is the angle made by the intersection of the top line of the cartilage and the baseline, which represents the degree of cartilaginous acetabular development. Normally, the α angle should be ≥ 60°. If the degree is decreasing, it can be diagnosed as hip dysplasia or even dislocation, and the ratio of the diameter of the femoral head located in the acetabulum to the diameter of the whole femoral head is normally above 50%. The dynamic method involves having the child in an active or passive flexion position of the hip joint to assess the corresponding anatomical relationship between the femoral head and the acetabulum, with or without signs of prolapse.