Insulin is the only hypoglycemic hormone, and the primary drug to treat diabetes. Recent studies found that high-dose insulin treatment of diabetes has become one of independent risk factors of progressing of diabetic retinopathy. Studies have shown that insulin can promote the development of diabetic retinopathy by promoting cell proliferation, destroying the blood-retinal barrier, promoting the proliferation of new vessels, affecting glutamate metabolism and inducting oxygen free radicals, etc.