The growth of the long bones of the lower limbs and the spine is the key to children’s height growth. The main components of bones are calcium and protein, therefore, calcium nutritional status directly affects the growth of children’s height. Calcium nutritional status requires certain conditions, and blood calcium levels cannot be used to determine the body’s calcium nutritional status. Under normal conditions, human blood calcium levels are tightly regulated, and only in cases of extreme calcium deficiency or short-term high calcium intake do blood calcium levels fall or rise slightly. Urine calcium correlates with calcium intake in healthy adults, but does not reflect calcium nutritional status in growing children. The clinical value of calcium generation has also not been proven. Bone density, with its advantages of speed, accuracy, low radioactivity and high reproducibility, is considered the most ideal indicator to assess the bone mineral content of the human body and indirectly reflect the calcium nutritional status of the human body, and it is the most suitable monitoring method to reflect the calcium nutritional status of children compared with other testing methods. Children in the growth and development period, it is best to test the bone density once a year to guide the need for calcium supplementation, trace elements in the blood calcium can not be timely and good response to the child’s calcium deficiency.