The kidney is one of the organs most prone to cysts in the human body, and related diseases include polycystic kidney, simple renal cyst, acquired renal cyst, medullary spongy kidney and parapelvic cyst, which can occur at any age and have a high incidence. There is a genetic component to the formation of renal cysts, but there is cystic epithelial hyperplasia and abnormal secretion of cystic fluid during their formation. Renal cystic disease often has no characteristic clinical symptoms, and most patients are aware of it only when other diseases are examined or during health checkups. Its clinical manifestations vary depending on the size, number and location of cysts, whether they are in a developing or quiescent state, and whether they are accompanied by bleeding, calcification, infection, malignancy, hypertension, or renal function impairment. There can be soreness and pain in the back or lumbar region, and an abdominal mass can be felt when the cyst is large. Definitive diagnosis must rely on imaging tests, mainly ultrasound, CT and magnetic resonance imaging (MR). Ultrasound is the diagnostic method of choice for renal cystic disease, it is non-invasive, it can distinguish more correctly the nature of the mass (cystic or parenchymal) and it can detect masses as small as 1.5 cm in diameter. The diagnosis will generally be confirmed in 98% of cases, while 2% may be overlooked or misdiagnosed, usually in hematomas, limited effusion or isolated cysts. Cysts are also easily missed or misdiagnosed when they are too small in diameter, when the wall is calcified, when there is intracapsular bleeding or infection, and when the patient is overly obese. Intravenous urography (IVU) can show signs of pelvic calyx compression, manifested as displacement, elongation, deformation of the renal pelvis or calyces, etc. Sponge kidney and polycystic kidney have their characteristic imaging, which is meaningful for diagnosis. The correct rate of differentiating cystic and parenchymal occupying lesions is about 70%. CT has a correct diagnosis rate of over 90% for cystic and parenchymal occupying lesions. The few incorrect diagnoses are mainly attributed to technical factors, usually occurring in small renal cysts, which is a problem caused by partial volume effects. Magnetic resonance (MR) has the unique advantage of determining the composition of the cystic fluid, which facilitates the determination of the nature of the cyst. Since MR does not use contrast contrast, end-stage to renal failure patients can opt for MR to understand renal lesions. The differential diagnosis is mainly distinguished from hydronephrosis, renal cell carcinoma, renal malformation tumor, cystic kidney cancer and extra-renal tumor.