Nutcracker syndrome, or left renal vein compression syndrome, also known as nutcracker phenomenon (NCP), occurs in males from adolescence to about 40 years of age, with childhood onset distributed between 4 and 7 years of age, and most often seen at 13 to 16 years of age. The left renal vein travels between the abdominal aorta and the superior mesenteric artery, and these two arteries form a 40-60 degree angle through which the left renal vein just passes. Anatomically, the right renal vein injects directly into the inferior vena cava with a short and straight stroke. The left renal vein, on the other hand, needs to cross the angle between the abdominal aorta and the superior mesenteric artery and cross the abdominal aorta before it can be injected into the inferior vena cava, so the left renal vein is much longer than the right renal vein. In normal time, the angle between superior mesenteric artery and abdominal aorta is filled by mesentery, fat, lymph nodes and peritoneum, so that the left renal vein is not squeezed. When puberty is faster, rapid growth in height, hyperextension of the spine, drastic changes in body shape or renal prolapse, the left renal vein has a bad time in this angle of entrapment and will be squeezed, causing changes in blood flow and corresponding clinical symptoms Nutcracker phenomenon’s main symptoms are hematuria and proteinuria, of which asymptomatic meatus hematuria is more easily detected. The cause of hematuria is compression of the left renal vein resulting in renal venous hypertension, bruising of the periureteral and genital veins draining from the dilated left renal vein, abnormal traffic with the renal collecting system, or thinning and rupture of part of the vein wall, causing non-glomerular hematuria, and also bruising of the testicular and ovarian veins resulting in cribriform pain, which is aggravated by standing or walking. In addition, men can develop varicocele. In addition, there is proteinuria, irregular menstrual bleeding, and hypertension. The diagnostic criteria for this disease are: bleeding from one kidney; non-glomerular urine red blood cell pattern; normal urinary calcium excretion; cystoscopy for left ureteral orifice spurting blood or hematuria; and dilated left renal vein visible on abdominal ultrasound or CT examination. Ultrasound has obvious advantages for the diagnosis of Nutcracker syndrome. The anatomy of the abdominal aorta, superior mesenteric artery and left renal vein can be clearly displayed during ultrasound examination, and the maximum internal diameter of the proximal segment of the dilated left renal vein can be found in different cross-sections with accurate measurement, and the change of the angle between the superior mesenteric artery and the abdominal aorta can be observed and measured at the same time. Ultrasound flow velocity provides a more accurate picture of hemodynamic changes, which can help in the diagnosis of this disease. Ultrasound can also exclude congenital malformations, trauma, tumors, hematuria caused by stones, infectious diseases and vascular abnormalities. In children with asymptomatic hematuria and upright proteinuria caused by nutcracker phenomenon, no specific treatment is needed, only follow-up. Only a few children who present with persistent hematuria with pain require left renal vein shunts. In some adult patients with severe persistent and recurrent hematuria, painful bleeding, and varicocele, conservative treatment is ineffective and surgical treatment is required. schepper first reported this syndrome in 1972 and attracted attention. Initially reported in China in the 1990s, the syndrome is not uncommon, mainly because physicians are unaware of the disorder and can easily misdiagnose it. The syndrome should be routinely ruled out in children and adults with persistent microscopic hematuria, intermittent meatus hematuria or with painful, varicose veins of the spermatic cord.