Renal cysts can be categorized into simple renal cysts as well as acquired renal cysts. The mechanism of simple renal cysts is still unclear and may be related to a variety of causes, while acquired renal cysts may be related to renal failure. 1. Simple renal cysts: the pathogenesis has not been fully elucidated, and is currently considered to be acquired. There are more views about its mechanism, such as occlusion of renal tubules and peripheral blood vessels, loss of contact between renal pelvic diverticulum and collecting system, renal parenchyma ischemia and renal tubular obstruction caused by local inflammation. 2. Acquired renal cysts: Acquired renal cysts may be related to renal failure, because after the occurrence of renal failure, due to the need for dialysis, which may reduce the effective renal units, it will make the incidence of acquired renal cysts higher. After discovering renal cysts, it is recommended to seek medical treatment as soon as possible for appropriate examination and treatment to avoid causing other complications.