Whether diabetic proteinuria 400mg/L needs treatment, first of all, the cause of proteinuria should be clarified, and then to target the cause of treatment. If it is caused by physiological reasons, usually do not need treatment. If it is caused by diabetic nephropathy, it is recommended to follow the doctor’s advice to actively control blood glucose. Under normal circumstances, when plasma flows through the glomerulus, only a small amount of protein with a small relative molecular mass passes through the glomerular filtration membrane, and proteins with a medium or large relative molecular mass cannot be filtered. Most of the protein in the original urine is reabsorbed by the renal tubules, and the urine contains only a very small amount of protein, which cannot be measured by conventional chemical characterization methods. When the urine protein content>150mg/24h or urine protein concentration>100mg/L, the routine chemical characterization test is positive, called proteinuria. When positive urine protein is found, it is recommended to seek medical attention in time to clarify the cause of the disease under the guidance of the doctor. If the cause is physiologic, no treatment is needed. If the cause is pathologic, such as diabetic nephropathy, it is recommended to follow the doctor’s instructions to control blood glucose levels, control blood pressure, and adjust blood lipids. If diabetic proteinuria 400mg/L occurs, it is recommended to consult a doctor in time, under the guidance of the doctor, improve the relevant examination, and take appropriate treatment measures.