One and a half year old baby walking O-shaped legs may be normal, that is, physiological O-shaped legs, may also be abnormal, that is, pathological O-shaped legs. 1. Physiological O-shaped legs: one and a half year old babies have just learned to walk, not yet stereotyped, at this time walking O-shaped is normal, clinical significance is not great, this situation can continue to observe. If the baby learns to walk for a period of time, still O-shaped legs, it may be genetic. It may be that the father or mother is O-shaped legs, inherited to the child. This situation can be corrected in the hospital. 2. Pathological O-shaped legs: if the baby’s parents are not O-shaped legs, may be suffering from vitamin D deficiency rickets, need to go to the hospital in time for examination, follow the doctor’s instructions to supplement calcium and vitamin D. Generally after a period of time after the treatment, the O-shaped legs will be improved. Baby O-shaped legs, to pay attention to, if the baby also exists excessive sweating, occipital baldness, night terrors and other symptoms, then should seek medical attention as soon as possible, so as not to delay the condition.