Vitamin D can regulate calcium and phosphorus metabolism and maintain bone health. In recent years, more and more studies have shown that vitamin D and its receptors have the potential to protect diabetic nephropathy. Animal studies and clinical trials have shown the correlation between vitamin D levels and the risk of diabetic nephropathy. Supplementation of vitamin D or its analogs can improve endothelial cell damage, reduce inflammation, proteinuria, and renal fibrosis and thus delay the process of diabetic nephropathy. Therefore, vitamin D and its receptor are expected to become a new choice for the prevention and treatment of diabetic nephropathy. This review summarizes the new research progress of vitamin D on the protective mechanism of diabetic nephropathy.