The morbility of bronchial asthma is gradually increasing year by year all over the world. Numerous studies have demonstrated that bronchial asthma is close related with immunoregulation. Vitamin D3 is involved to immune regulatory mechanisms in bronchial asthma, including regulating cytokine, Treg, matrix metalloproteinases-9. Considering the influence of vitamin D3 on the immune regulatory of bronchial asthma, it is provided a theory evidence that vitamin D can be used in the treatment of bronchial asthma effectivly and a novel method of immune treatment for children with bronchial asthma eventually.