First, family genetic history. Polycystic kidney disease is an autosomal dominant genetic disease with a genetic probability of 50%. People with polycystic kidney disease often have similar patients in the family; while multiple renal cysts have no family genetic history. Second, the age of onset. Polycystic kidney disease often occurs in middle age, especially after the age of 40. Symptoms, pain, and abdominal lumps begin to appear; and multiple renal cysts can occur at any age. Third, the size of the kidney. The progression of kidney disease on both sides of the polycystic kidney is asymmetric, the size of the kidney is different, there are multiple cysts on the surface of the kidney, and the shape of the kidney is irregular; while multiple-type renal cysts will not change the shape of the kidney. Fourth, the contents of the capsule. Polycystic kidney is urine, and multiple renal cysts are body fluids. Fifth, complications and harm. Polycystic kidney disease is a large and small cyst over the entire kidney. If not controlled in time, these cysts will grow up with age. Over time, they will compress the kidneys, damage the structure of the kidneys, and reduce the number of nephrons that produce urine. , An increase in serum creatinine or a decrease in glomerular filtration rate eventually develops into end-stage renal failure. At the same time, it can cause high blood pressure, polycystic liver and other diseases. However, multiple renal cysts will not cause hypertension, polycystic liver and so on.