6 months baby leg joint muscle asymmetry, need to be alert to congenital hip dislocation, femoral head dysplasia, once diagnosed, can be reset by manipulation, or double lower limb orthosis fixation, if necessary, surgical treatment, there may be a normal situation, no special treatment. 1. Congenital hip dislocation: at this time, the baby not only has joint muscle asymmetry, but also can be accompanied by abnormal hip joint activities, such as abduction, external rotation obstacles, once diagnosed, can be reset by manipulation at an early stage, and if necessary, surgical treatment. 2. Femoral head dysplasia: double lower limb orthosis can be fixed to squeeze the hip joint to promote the development of the femoral head, most of them have a good prognosis, and a few of them with bad prognosis may need surgical treatment. 3. Normal situation: if the baby is fat, excessive leg fat, can also cause joint muscle asymmetry, but the joint activity is normal, no special intervention. In conclusion, when the baby appeared leg joint muscle asymmetry, it is recommended to consult the pediatric surgery in a timely manner to clarify the cause of the disease and take targeted treatment.