Polycystic kidneys and renal cysts can be differentiated by history taking, site of onset, characteristics of the cysts, and the presence of normal renal tissue around the cysts. 1. History taking: polycystic kidney is an autosomal dominant disease with family history, and polycystic kidney is mostly combined with polycystic liver; renal cysts are mostly not combined with polycystic liver. 2. Site of disease: polycystic kidney is usually bilateral, and can be unilateral in early stage; renal cysts are more common in unilateral. 3. Characteristics of cysts: polycystic kidneys have many and dense echogenic zones, which are diffusely distributed and difficult to be counted; renal cysts are few in number and scattered in distribution. 4. Distribution of cysts: cysts of polycystic kidney are distributed in the renal cortex and medulla, and renal cysts are mostly distributed in the cortex. It is recommended that patients go to regular hospitals, complete the relevant examinations under the guidance of the doctor to identify and follow the doctor’s instructions for treatment.