Calcium is the most abundant metal element in the human body. In general, the adult body contains about 1200 grams of calcium in total, accounting for 1.5%-2.0% of body weight. Ninety-nine percent of this calcium forms bones, and another 1% or so is present in free form in the blood, extracellular fluid and soft tissues. Calcium is important for human health. Calcium forms bone and teeth, and has many other important roles such as reducing capillary and cell membrane permeability, preventing exudation, controlling inflammation, activating enzymes, maintaining neuromuscular excitability and heartbeat rhythm, and participating in the coagulation process. Calcium is the most abundant metal element in the human body, but it is also one of the elements that are easily deficient. Insufficient calcium nutrition will cause many adverse consequences to the body, children’s calcium deficiency will affect growth and development, and will lead to children’s rickets, “X” leg or “O” leg; adolescent calcium deficiency will lead to slow growth, lack of concentration, easy to allergic, paranoid, irritable Calcium deficiency in pregnant and lactating women is detrimental to the development of the fetus; calcium deficiency in the elderly can lead to osteoporosis and increase the risk of fracture. Calcium deficiency can be supplemented by medication or food, and if necessary, vitamin D supplementation, sun exposure to promote calcium absorption, alleviate calcium loss and enhance bone quality.