Causes of children’s legs mainly include vitamin D deficiency rickets, premature load overweight, as follows: 1, vitamin D deficiency rickets: children’s growth and development is very rapid, the demand for vitamin D and calcium is relatively high, if there is no timely supplementation will lead to children with vitamin D deficiency rickets, children’s bones will be softened after the disease, thus resulting in the rotunda legs; 2, Early load too heavy: if children’s lower limbs load too early will also cause rotator cuffs, such as practicing walking too early, 8 months or so began to apply the walker to walk, or family poverty will be too early to participate in the labor, will also lead to lower limb overload caused by rotator cuffs.