Parapelvic cyst is a kind of renal cyst, which is a cystic lesion growing next to the renal pelvis, which may cause pressure on the renal pelvis and renal hilum, producing symptoms of hydronephrosis or pain in the kidney. The treatment principles are the same as those for renal cysts. A volume of less than 4 cm can be observed clinically, without symptoms of compression or urinary tract obstruction, and the ultrasound can be reviewed regularly. If the volume increases further, producing compression symptoms, causing hydronephrosis, causing back pain and infection or the volume exceeds 4cm, ultrasound-guided cyst puncture and aspiration can be chosen, or surgery can be chosen. Cyst puncture aspiration is prone to recurrence, but it is not more invasive and is a minimally invasive type. The surgery requires open or laparoscopic surgery to remove the cyst and the cyst wall with satisfactory results and no recurrence.