Clinically, diabetic nephropathy is generally divided into early stage and clinical diabetic nephropathy stage II. The main basis of the classification is the amount of urinary albumin excretion, early stage is the microalbuminuria stage, and clinical diabetic nephropathy is the obvious albuminuria stage. In recent years, based on long-term studies and follow-up observations of patients with type 1 diabetes mellitus (T1DM), a more comprehensive understanding of the entire development of T1DM nephropathy has been obtained, and detailed staging of nephropathy has been done. For patients with type 2 diabetes mellitus (T2DM), there is no fine staging because the time of onset is often not determined, as well as the lack of long-term follow-up data, and now the staging method of T1DM is also referred to. For T1DM diagnosis at the time of glomerular hyperfiltration and hypertrophy enlargement. Increased glomerular and renal volume is the prominent manifestation. There is transient microalbuminuria, which can disappear after treatment with insulin. Glomerular filtration rate is high and can be reduced with treatment, but often does not return to normal. If the onset of T1DM is before puberty, this phase lasts longer. The detailed staging of diabetic nephropathy is divided into five stages, and the characteristics of each stage are as follows: 1. Stage I: for T1DM at the time of diagnosis glomerular hyperfiltration and hypertrophy enlargement. Increased glomerular and renal volume is the prominent manifestation. There is transient microalbuminuria, which can disappear after treatment with insulin. Glomerular filtration rate is high and can be reduced after treatment, but often does not return to normal. If the onset of T1DM is before puberty, this stage lasts longer. 2.Stage II: There is kidney damage, but no clinical signs. This stage appears two years after the onset of diabetes, and some patients continue in this stage for many years, even for life. The glomerular basement membrane is usually thickened and the thylakoid area is often hyperplastic. Microalbuminuria may occur with poorly controlled diabetes (often ketosis) and exercise and is reversible. Glomerular filtration rate remains significantly increased. Blood pressure is normal. 3.Stage III: It is the “high-risk stage” of diabetic nephropathy, typically after 10-15 years of diabetes. Microalbuminuria is increasing. Glomerular filtration rate is still increased. Blood pressure begins to increase. Longitudinal studies show that anti-hypertensive treatment significantly improves microalbuminuria. Treatment with insulin pump or intensive treatment at this stage can reduce or stabilize urinary albumin excretion after significant improvement of blood sugar. In contrast, those who are treated conventionally are prone to develop to the stage of obvious nephropathy. 4.Stage IV: The duration of the disease is more than 15-25 years, and about 40% of T1DM patients develop to this stage. Typical changes in pathology appear, while the diagnosis is mainly based on clinical manifestations, increased urinary protein excretion (>0.5g//24h), hypertension in most patients, and glomerular filtration rate begins to decline. Effective anti-hypertensive therapy can slow down the rate of glomerular filtration rate decline. 5. Stage V: End-stage renal failure, characterized by widespread glomerular capillary occlusion with glomerular glassy changes, glomerular filtration rate has been very low, nitrogen retention and hypertension is obvious. Not every patient with T1DM will go through the above 5 stages, instead most patients only stay in the first two stages and still have no significant kidney damage after 20-30 years of disease. However, once the disease has progressed to stage III, i.e. microalbuminuria, it is likely to continue to progress to stage IV and develop typical diabetic nephropathy. Treatment should try to keep the disease in stage III, once it reaches stage IV, the course of the disease is irreversible and most patients will enter end-stage renal failure.