Inflammatory bowel disease (IBD) is a group of chronic inflammatory diseases of the intestine mediated by abnormal immunological mechanism caused by multiple etiological factors.The main treatment at present is anti-inflammation and immunosuppression,but with severe side effects and poor efficacy.Vitamin D3 has immunoregulatory,anti-inflammatory,and antineoplastic functions.Vitamin D,as a novel immunoregulator,may provide a new treatment option for patients with IBD.This article will review the research progress on the following four aspects:the relationship of vitamin D with innate immunity,adaptive immunity,and pathogenesis of IBD,and vitamin D supplement in IBD patients.