Membranous nephropathy is one of the most common causes of adult nephrotic syndrome. If it is not diagnosed and treated effectively in time, it seriously affects patients’ work and quality of life, and some patients will slowly progress to chronic renal insufficiency. According to the different causes, membranous nephropathy can be divided into idiopathic membranous nephropathy and secondary membranous nephropathy. Idiopathic membranous nephropathy refers to those that cannot be identified or the cause is not found temporarily, while secondary membranous nephropathy refers to membranous nephropathy that has a clear cause. A very important part of the diagnosis and treatment of membranous nephropathy is to identify the cause of membranous nephropathy. The causes are more common and less common Autoimmune diseases Systemic lupus erythematosus Rheumatoid arthritis Mixed connective tissue disease, dermatomyositis, ankylosing spondylitis, systemic sclerosis, myasthenia gravis, herpetic aspergillosis, hyperthyroidism, Hashimoto’s thyroiditis Infections Hepatitis B virus infection Hepatitis C, malaria, filariasis, syphilis, leprosy, cysticercosis, infective endocarditis Drugs and toxicity Gold agents, mercury, penicillamine, antipyretic and analgesic drugs: ibuprofen, diclofenac, etc. Buspiramine, methamphetamine, propoxur, trimethoprim, lithium, volatile organic solvents: formaldehyde, paint, house decoration pollution. Tumors Digestive and respiratory system tumors, thyroid tumors Other rare tumors