Vitamin D plays an important role in calcium absorption and bone metabolism. More and more studies have found that vitamin D is also involved in the modulation of infection，inflammatory and immune responses.Vitamin D also plays an important role in regulating a variety of cells. Vitamin D insufficiency and deficiency are common worldwide，which is more common in children with bronchial asthma. The pathophysiology of bronchial asthma is chronic inflammation，airway hyperresponsiveness and airway remodeling. Vitamin D may affect the occurrence and development process of asthma. This review summarized the correlation between vitamin D and the morbidity of asthma，the mechanisms of vitamin D affecting asthma，and the clinical effects of vitamin D as an adjuvant therapy for childhood asthma.