Renal cysts have the potential to affect the function of the kidney, commonly seen in multiple renal cysts or polycystic kidneys, in which case the kidney is encapsulated or destroyed by multiple cysts, causing damage to the renal parenchyma or damage to the effective renal units, which can result in renal function impairment, especially in congenital polycystic kidney lesions, which eventually and inexorably lead to renal failure due to destruction of the renal parenchyma. Acquired renal cysts, also known as simple renal cysts, do not produce significant damage to the kidney, progress very slowly and are not large in size, and generally do not produce compression and damage to the renal parenchyma. Unless the gradual increase in size has caused damage to the renal parenchyma, at which time abnormal renal function may occur, but generally acquired renal cysts are single unilateral lesions, so normal contralateral renal function indicators will not have any effect on the function of the kidney. CT examination is needed for renal cysts, which can clearly determine the number and size of cysts and their damage to renal parenchyma, and further evaluate the impact on renal function in the future.