Asymmetry of thigh lines in infants may be a normal phenomenon, but be alert to the presence of congenital hip dysplasia. 1. Normal phenomenon: infants with asymmetrical thigh lines are considered to be a physiological phenomenon, a part of infants’ thigh lines may have this problem, as long as the vitality of the limbs, muscle tone, and abduction are normal, there is no need to worry. 2. Congenital hip dysplasia: it will lead to the activity disorder of the joints, the double lower limbs will form the problem of asymmetry of leg lines because of the non-uniformity of development, the formation of ball and socket joint changes in the hip joint area, and the length of the two legs is not the same. Asymmetrical thigh lines in infants are suspected to have congenital hip dislocation or dysplasia, and it is recommended to consult the Pediatric Surgery Department of regular hospitals.