As a newly discovered gas signal molecule after nitric oxide and carbon monoxide, hydrogen sulfide (H₂S) has attracted wide attention from experts and scholars both at home and abroad, and has been carried out a lot of physiological and pathophysiological studies. Most scholars believe that H₂S plays an important role in the development of diabetes and its microvascular disease. However, so far, the physiological and toxic effects of H₂S in the human body are not completely clear, and most of the mechanisms of the H₂S effect have not been fully elucidated. This paper reviews the role and mechanism of H₂S in 3 common diabetic microangiopathy (diabetic retinopathy, diabetic neuropathy and diabetic nephropathy), in order to provide a new theoretical basis for the research and treatment of diabetic microangiopathy.