Diabetes mellitus (DM) is one of the most important chronic diseases currently threatening human health worldwide.However,Diabetic kidney disease (DKD) is one of the main microvascular complications of DM;Vitamin D is a steroid hormone that is expressed in bone,kidney,intestines and other tissues.Vitamin D not only plays an important role in regulating calcium and phosphorus metabolism,but also involves the multiple biological effects of immune regulation,inflammatory response,cell proliferation and differentiation.In this paper,the effects of vitamin D on DKD and its research progress are discussed.