Whether 3-year-old babies still need to take vitamin D every day, need to be analyzed according to the specific circumstances of the comprehensive analysis, the lack of supplementation, not the lack of supplementation is not necessary. Under normal circumstances, the daily diet contained in the nutrition can meet the baby’s need for vitamin D, do not need to take additional vitamin D supplementation, usually parents can take the baby moderate amount of outdoor exercise, sunbathing and so on. If the baby has symptoms of vitamin D deficiency, such as sleep disturbance, night sleep sweating more, growth retardation and other symptoms, it is recommended to go to the hospital in a timely manner, a clear diagnosis, and then take vitamin D under the guidance of a professional doctor. Parents should not give their babies vitamin D supplementation privately to avoid excessive intake of vitamin D, which may cause adverse effects, and it is recommended to take it in strict accordance with medical advice.