There are about 40 causes of hematuria, most of which are caused by diseases of the urinary tract itself, and a few are related to systemic and other systemic diseases. Common causes of hematuria: urinary tract infection, stones, tumors, prostatic hyperplasia, injury, tuberculosis, etc. Hematuria is an important clinical symptom, and once it occurs, a comprehensive and thorough examination should be performed, including urinary routine, bacterial culture, cytological examination, X-ray imaging, cystoscopy, ultrasound, CT, and renal puncture biopsy if necessary. Asymptomatic microscopic hematuria should not be ignored either. According to statistics, more than 50% of urological patients with infections, 67% of patients with stones, 40% of patients with tuberculosis, and 20% of patients with tumors show microscopic hematuria. Therefore, microscopic hematuria is as important as visual hematuria, and its clinical significance should never be overlooked because of the slight amount of blood. If the cause of hematuria is not identified after systematic urological examination and medical examination, it must be checked and reviewed regularly.