Positive urinary occult blood usually refers to the presence of red blood cells in the urine, which may be physiological or caused by nephritis, urinary tract infection, stones and other pathological factors. Physiologic causes are more common in cases such as strenuous exercise and fever. Pathological causes are more common in various acute and chronic nephritis, urinary tract infection, stones, tuberculosis, urinary tract tumors or systemic coagulation dysfunction. If women do not clean the vulva during menstruation, menstruation can contaminate the urine sample, which can also lead to positive urinary occult blood. Positive urinary occult blood, need to review the urine routine, if still positive urinary occult blood, need to improve the urinary ultrasound, urine erythrocyte phase difference morphology and other tests, clear cause of the disease, and then follow the doctor’s instructions for targeted treatment.