The necessary basis for the diagnosis of nephrotic syndrome is the diagnostic criteria for nephrotic syndrome. There are four diagnostic criteria, namely, edema, massive proteinuria, hypoproteinemia, and hyperlipidemia. As long as these two conditions are present, nephrotic syndrome can be diagnosed. But nephrotic syndrome is a clinical manifestation caused by a series of diseases, not a disease, such as fever and anemia is a manifestation, not a disease. Further diagnosis should be made to exclude whether it is primary nephrotic syndrome or secondary nephrotic syndrome. If secondary factors are excluded, is there a series of factors that can cause secondary nephropathy such as allergic purpura, systemic lupus erythematosus, diabetes mellitus, hypertension, multiple myeloma, amyloidosis, etc. If the above factors are excluded, primary nephrotic syndrome can be diagnosed. There are five common clinical pathological types of primary nephrotic syndrome, microscopic lesions, membranous nephropathy, focal segmental proliferative sclerosing glomerulonephritis or FSGS, membranous proliferative glomerulonephritis, and thylakoid glomerulonephritis. Clear diagnosis by renal puncture is required, so the clinical diagnosis of nephrotic syndrome is relatively simple, but seeking the root cause requires further consideration of multiple factors, such as primary and secondary, as well as pathological diagnosis.