A parapelvic cyst is a benign cyst originating from the renal hilum at the renal parenchyma and does not communicate with the collecting system. The etiology is lytic dilatation, probably due to chronic inflammation. It is mainly associated with compression of the renal collecting system or renal tip artery and complications caused by the cyst, manifested by symptoms such as back pain, hypertension, hematuria and urinary tract infection, and the presence or absence of symptoms is highly correlated with the location and size of the cyst and its complications. The initial diagnosis of this disease depends on imaging examination, CT examination is most definitely useful in the diagnosis of this disease, IVP examination also has a high accuracy rate in the diagnosis of this disease, it can understand the bilateral renal function, the morphology of the renal collecting system and complications, it is easy to suggest the occupying lesion at the renal hilum and should be used as a routine examination. ultrasound is sometimes easy to misdiagnose as hydronephrosis in the diagnosis of this disease, in ultrasound examination suggesting unexplained CT scan shows that the cyst is located at the renal hilum, separated from the normal renal parenchyma, and the lowest density halo around the cyst is the characteristic manifestation of parapelvic cyst, and the CT scan of parapelvic cyst can be similar to hydronephrosis, but there is no enhancement on the enhanced scan, and the contrasted renal pelvis and calyces are compressed and elongated, which can set off the cyst more clearly. The diagnosis of parapelvic cyst is clear based on the above history and ancillary tests. The differential diagnosis of parapelvic cyst is as follows: 1. Hydronephrosis: hydronephrosis can be caused by multiple factors within and outside the urinary system, congenital and acquired, and can occur in all age groups. Patients mostly have no obvious clinical symptoms, and when hydrocele is serious, there can be a feeling of swelling in the waist and abdominal mass. Patients with intermittent hydronephrosis caused by stones may develop renal colic with nausea, vomiting, abdominal distention and scanty urination. In severe cases of hydronephrosis, enlarged kidneys may be palpable on examination, and in case of co-infection, pus urine and systemic infection symptoms may appear. Diagnosis mainly relies on ultrasound, IVP, CT and MRI, etc. 2.Renal tumor: It is a common tumor in the urinary system, divided into benign and malignant, benign tumor is rare. Benign tumors mostly have no typical clinical symptoms, but when they are larger, they may cause pain and discomfort in the lower back and abdomen, and the enlarged kidney can be palpated on body examination. The typical clinical manifestations of malignant tumors in kidney are hematuria, lumbar pain and mass. The diagnosis mainly relies on ultrasound, enhanced CT and MRI, etc. It mostly presents as solid occupying lesions, each with cystic solid features. Parapelvic cysts are benign lesions with small and asymptomatic cysts and can be followed up regularly, but when the diameter of the cyst is >5 cm, or when pressure symptoms and complications appear, surgery should be actively taken. Surgical methods include open cyst decompression, B-ultrasound guided aspiration of intracapsular fluid with injection of sclerosing agent and laparoscopic cystectomy. Because of the complex structure of renal portal and deep cyst, puncture and aspiration of intracapsular fluid for injection of sclerosing agent is very easy to cause complications and high recurrence rate, so it is not suitable. Traditional open surgery requires a large incision in the lumbar region, which causes great damage to the body, slow postoperative recovery and long hospital stay. Laparoscopy is worth promoting in clinical practice because of multi-angle observation and magnification, adequate intraoperative exposure, good hemostasis and minimally invasive. There are reports of curing parapelvic cysts by B ultrasound-guided puncture and aspiration of cystic fluid. This method may be a better treatment for simple parapelvic cysts, but because parapelvic cysts are adjacent to the renal hilum vessels, the operator should have a more skilled technique of puncturing renal cysts to prevent serious complications. Laparoscopic surgery for parapelvic cysts requires a high level of operator skill, and we should pay attention to the following points: (1) Preoperative clarification of the location, size, number of cysts and the relationship with surrounding vessels and renal collecting system; (2) Care should be taken when separating parapelvic cysts because of their proximity to the renal hilum; the walls of the renal veins and inferior vena cava are dark blue under laparoscopy, which are similar to the top of the cysts, and should be identified and operated carefully to (3) If the cyst is indistinguishable from the dilated renal pelvis, the pelvis can be squeezed, and the renal pelvis will become hollow, while the cyst will remain unchanged. (4) The wall of the cyst should be removed 3-4 mm from the parenchyma to avoid uncontrollable renal parenchymal hemorrhage; (5) In case of unclear anatomical view, variation, or hemorrhage, the surgery should be promptly transferred to open surgery; (6) Filling the hilar fat in the parapelvic cyst can further prevent postoperative recurrence; (7) The urologist is familiar with the posterior abdominal anatomy, and the unilateral parapelvic cyst can be treated by the retroperitoneal route, while the bilateral cysts can be treated by the transabdominal route at the same time. The minimally invasive advantages are fully exploited. Laparoscopic techniques are safe and reliable for the treatment of parapelvic cysts, fully reflecting the minimally invasive advantages of laparoscopic surgery. With the increasing popularity and development of laparoscopic technology, laparoscopic cyst debulking will definitely become the preferred method for the treatment of parapelvic cysts.