Bone density is an important indicator of bone quality, reflecting the degree of osteoporosis and predicting the risk of fracture. Clinically, the T value is usually used to determine the normal value of bone density, the normal value reference range between positive +1 to -1, below -2.5 is osteoporosis, through the bone density test to determine whether the infant is calcium deficient, calcium nutrition is insufficient to affect the deposition of calcium in the bones, causing low bone density. Infants should be taken outdoors more often to receive sufficient sunlight, eat more calcium-rich foods to ensure adequate calcium intake, and undergo treatment or dietary adjustment under the guidance of a professional pediatrician.