A new term that has emerged in medicine in recent years is the nutcracker phenomenon. When we hear nutcracker, we may think of a delicious pecan, to eat it you need to use a nutcracker to crack its hard shell. But today we are talking about Nutcracker Phenomenon, which is the name of a medical condition. Nutcracker phenomenon, also known as left renal vein compression syndrome, for the left renal vein into the inferior vena cava in the trip, due to travel in the abdominal aorta and the superior mesenteric artery between the formation of the angle of extrusion and clinical symptoms. The prevalent age is seen between 13-16 years of age and is a common cause of nonrenal hematuria in children. The hematuria produced is usually upright hematuria, i.e., hematuria occurs when the body is upright and disappears in the prone position, and is most common in taller, thinner adolescents, and rare in those over 30 years of age. It is characterized by non-glomerular hematuria, but a small number of patients can present with glomerular hematuria and can be combined with upright proteinuria. Patients have a good prognosis and most hematuria slowly improves in adulthood. Nutcracker phenomenon in the hospital clinic, usually appear the following symptoms: First, hematuria is the most common symptom, microscopic hematuria is common, but also some manifested as naked eye hematuria, for non-glomerular hematuria. Second, there are some accompanying symptoms, such as pain in the coeliac region; male children can be accompanied by varicocele, which is also a cause of infertility in adulthood. There are also children with erectile dysregulation and chronic fatigue syndrome. Third, upright proteinuria: protein is negative when resting in the lying position, proteinuria increases significantly in the upright position, but the 24-hour urine protein is usually less than 1g. The diagnosis of the nutcracker phenomenon mainly relies on CT, ultrasound, renal venography. In terms of treatment, most of them can be treated conservatively, especially for those who have recurrent microscopic hematuria or intermittent short-term hematuria of the naked eye, but without anemia or abdominal pain, they do not need any special treatment, and follow-up can be done. For some serious persistent recurrent hematuria, bleeding pain, varicocele in adult patients, conservative treatment is poor, need surgery.