Calcium deficiency in five-year-old children can be improved by diet, environment as well as supplementation of vitamin D3 and calcium supplements, etc. Calcium supplementation should be carried out in accordance with the doctor’s advice and should not be taken by oneself. 1. Diet: Eat calcium-rich foods, such as meat, eggs, milk and other calcium-rich foods. Since the absorption rate of calcium in the human body is affected by a variety of factors, do not eat at the same time as calcium supplementation with oxalic acid-rich foods, such as bamboo shoots, amaranth and so on, so as not to affect the absorption of calcium. 2. Environment: Ensure half an hour of outdoor activities every day and give sunlight exposure to help calcium absorption, but need to avoid exposure to the sun, so as not to cause harm to the body. 3. Vitamin D and calcium supplementation: calcium supplementation should also pay attention to the intake of vitamin D. Vitamin D can effectively promote the absorption of calcium. If dietary supplementation, sun exposure, and vitamin D supplementation still can not improve the situation of calcium deficiency, you can follow the doctor’s instructions for calcium supplementation, such as calcium gluconate. Calcium deficiency in five-year-old children should be promptly consulted and treated in accordance with medical advice. All of the above medications should be used under the guidance of a doctor, avoid self-medication, so as not to cause harm to the body.