Nephrotic syndrome can be categorized into two main types according to the cause: primary or secondary, which are different for children, adolescents, middle-aged and old-aged people. 1. Children: primary nephropathy is mainly microscopic lesion nephropathy; secondary nephropathy includes allergic purpura nephritis, hepatitis B virus-associated nephritis, lupus nephritis. 2. Adolescents: primary include mesangial proliferative glomerulonephritis, microscopic lesion nephropathy, focal segmental glomerulosclerosis, etc.; secondary include lupus nephritis, purpura fulminans nephritis, hepatitis B virus-associated nephritis. 3. Middle-aged and old-aged: primary including membranous nephropathy; secondary including diabetic nephropathy, renal amyloidosis, myeloma nephropathy and so on. Patients with nephrotic syndrome should go to the hospital in time to see a doctor, clarify the cause of the disease under the guidance of a professional physician and get timely treatment.