Chronic specific complications of diabetes mellitus refer to microangiopathy of diabetes mellitus, and the typical pathological changes of microangiopathy are microcirculation disorder and microvascular basement membrane thickening. Microangiopathy can involve multiple tissues and organs throughout the body, mainly in the retina, kidney, nerves, and myocardial tissues, of which diabetic nephropathy and retinopathy are the most important. Diabetic nephropathy is divided into five stages, stage I appears in the early stage of diabetes mellitus, the glomerular intracapsular pressure is elevated, and glomerular filtration rate is increased; stage II glomerular filtration rate is still on the high side, and intermittent elevation of urinary microalbumin occurs; stage III is known as the early diabetic nephropathy stage, which is characterized by a persistent elevation of urinary microalbumin, and the urinary albumin excretion rate is between 20 and 200 μg/min; stage IV is known as the clinical diabetes mellitus Stage IV is called clinical diabetic nephropathy, with a further increase in urine albumin and a urinary albumin excretion rate of more than 200 μg/min, which may be accompanied by edema and elevated blood pressure; Stage V is the uremic stage, in which the majority of renal units are atretic, with a decrease in urinary albumin, an increase in blood creatinine, and a further increase in blood pressure. Diabetic retinopathy often occurs with diabetic nephropathy or successively, diabetic retinopathy is divided into 6 stages; I-III stage is non-proliferative retinopathy; IV-VI stage is proliferative retinopathy; I stage is the appearance of microangiomas or small hemorrhages at the same time in the retina; II stage is the emergence of hard oozing on the basis of this; III stage is the emergence of cotton-wool-like soft oozing on the basis of the II stage; In stage IV, there is neovascularization and accumulation of blood in the vitreous; in stage V, there is proliferation of fibrovascularization and vitreous mechanization; in stage VI, there is detachment of the tensor retinae, causing blindness.