Calcium is an important nutrient in the body, and the normal growth and development of bone tissue requires the intake of appropriate amounts of calcium. For infants and young children, the daily intake of appropriate amounts of calcium supplements can promote growth and development, and a healthy, safe and scientific calcium supplement is especially important. Among them, food is also an important source of calcium and vitamin D. Milk and milk products, green leafy foods such as lettuce, broccoli, chard, soy products, nuts, seafood, black fungus and meat are rich in calcium. Among them, milk is rich in nutrients and is the best source of calcium for human body, and the ratio of calcium to phosphorus is very appropriate and conducive to the absorption of calcium, so milk is the best calcium food for children. The breast milk of a healthy mother can meet the calcium needs of a full-term baby, but the vitamin D content in breast milk is low and needs to be properly supplemented with vitamin D to promote calcium absorption and prevent vitamin D deficiency rickets. Premature babies and low birth weight babies need calcium supplements. babies over 6 months old start to add complementary foods, in addition to eating breast milk, infant formula, more of these foods with high calcium content, as long as the diet is balanced, to ensure adequate intake of dairy products, no picky eating, partiality, conducive to maintaining the normal concentration of calcium in the body, can continue to supplement vitamin D until 2 years old. If the child’s diet is not scientifically sound, and if the child’s calcium intake is affected by a serious diet of picky eating, then calcium supplements are needed. A reasonable diet, intake of calcium-rich foods, food diversification and appropriate outdoor exercise can help to meet the demand for calcium and other nutrients and contribute to good health.