The level of Nogo-B was decreased in glomerular endothelial cells in biopsy specimens from DN patients. In vivo and in vitro studies have shown that silencing Nogo-B activated ER stress signaling and affected the expression of autophagy-related marker early growth response 1 (EGR1) and microtubule-associated protein light chain 3 (LC3) in endothelial cells in hyperglycemic condition. Conclusion and Innovation: These results denote that Nogo-B contributes to ER stress-mediated autophagy and protects endothelial cells in diabetic nephropathy, providing new evidences for understanding the role of ER stress-mediated autophagy in endothelial cells of diabetic nephropathy.