The developmental dislocation of the hip joint in infants shows as follows: 1, asymmetric skin pattern and unequal length of both lower extremities; 2, Allis test test, unequal length of both lower extremities combined with two knee joints; 3, abduction test; 4, Barlow test; 5, the infant femoral artery fluctuation sound is very small. After walking the child showed: 1, walking duck walk; 2, check the standing test; 3, both lower limbs are not equal; 4, X-ray shows Shen Tong’s line is not normal.