Three-year-old children love to sweat, usually with physiological factors, vitamin D deficiency, infections and other factors. 1. Physiological factors: in the case of hot weather, room airtight, will cause the body to sweat; or due to the child’s mobility, in the process of strenuous exercise, there will be a large amount of sweat, is a normal performance. 2. Vitamin D deficiency: long-term large-scale lack of vitamin D, affecting the absorption of calcium and phosphorus, will affect the development of the body, easy to induce hyperhidrosis. 3. Infection: for example, bacterial infection, viral infection and fungal infection, etc., pathogenic bacteria repeatedly stimulate the human organism will cause excessive sweating. Sweating in three-year-olds can also be caused by other factors such as hyperthyroidism and tuberculosis. It is recommended to go to the hospital in time, complete the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.