In our daily life, we can often find an interesting phenomenon, the children of friends have not seen a few years, some have grown into “small Yao Ming”, while some are still hovering at the level of “Pan Changjiang”. This and genetic, individual differences are certainly linked, but there is a key factor can not be ignored bone age. Children’s growth and development can be expressed in two “ages”, namely, age and bone age. Age is the number of years people say they are and does not truly reflect the maturity of a child. Bone age, on the other hand, is a biological age that is closely related to growth, and is often used as a criterion for defining biological age to evaluate a child’s growth and maturity. Bone age can be determined by radiographs of bones. There are a number of sites used to evaluate bone age, but the most common is the left wrist, followed by the knee. Because the left wrist is a representative part of the skeleton that is well developed throughout the body, and because it is small in size and requires a small dose of X-ray, it is generally used in clinical practice. The emergence of ossification centers, complete ossification, and closure of the backbone all occur in a certain time and order. Therefore, the comparison between bone age and actual age can be used to determine whether a child is developing too early or too late. Bone age that is one year ahead or one year behind is called abnormal, and is most commonly seen in endocrine diseases, such as precocious puberty in children and thyroid-deficiency dwarfism. For such causes of short stature, should be the right medicine, do not blindly take all kinds of market cluster of tonic products, to avoid “pull up seedlings to grow” tragedy. With the X-ray method of assessing bone age, mankind has undoubtedly looked at another card of God. For children who are expected to pursue careers with height requirements, such as athletes and dancers, bone age radiography is an easy way to find out whether they have the potential to excel or not.