In urological work, hematuria is one of the most common clinical symptoms. Many people in life do not pay enough attention to hematuria. Hematuria is defined as ≥3 red blood cells/HP in urine, >5 red blood cells/HP in centrifuged urine, or a 12-hour urine Addis count >500,000. Hematuria caused by urological diseases is most commonly associated with urinary tract infections, stones, tumors, urinary tract injuries, malformations, etc. 1, inflammation: acute and chronic glomerulonephritis, acute and chronic pyelonephritis, acute cystitis, urethritis, urinary tuberculosis, urinary mycobacterial infection, etc. 2, stones: stones in the renal pelvis, ureter, bladder, urethra, any part of the stone, when the stone moves through the urinary epithelium, that is easy to cause hematuria also easy to secondary infection. Large stones can cause urinary tract obstruction and even cause kidney function damage. 3, tumors: malignant tumors in any part of the urinary system or malignant tumors in neighboring organs invading the urinary tract can cause hematuria to occur. The most common one is bladder tumor. 4, trauma: refers to violence and injury to the urinary system. 5, drug stimulation: such as sulfonamide, phenol, mercury, lead, arsenic poisoning, massive infusion of mannitol, glycerol, etc. 6, congenital malformations: polycystic kidney, congenital ultra-thin glomerular basement membrane, nephritis. Nutcracker phenomenon, the disease is a congenital malformation of blood vessels caused by the extrusion of the left renal vein that travels between the abdominal aorta and the superior mesenteric artery, causing intractable microscopic hematuria called nutcracker phenomenon. The right renal vein injects directly into the inferior vena cava, while the left renal vein must cross the angle formed by the abdominal aorta and superior mesenteric artery to inject into the inferior vena cava. Normally, this angle is 45°~60°, but if this angle is congenitally too small or filled with mesenteric fat, enlarged lymph nodes or peritoneum, it can cause nutcracker phenomenon. Diagnosis is based on CT, ultrasound, and renal venography. Treatment must be surgically corrected. Therefore, if you have hematuria, you should go to the hospital in time to avoid delaying the diagnosis and treatment of the disease.