The possible causes of frequent urination, painful urination and blood during urination are: 1. Infection of the urinary tract, when the acute infection period, there can be obvious symptoms such as frequent urination and urgent urination. When the inflammation invades to the whole bladder mucosa and the whole urethra mucosa, mucosal congestion can occur, and this can be accompanied by hematuria during urination. It is recommended to retain urine for routine urine or culture examination. If a large number of white blood cells and red blood cells are seen in the routine urine, the diagnosis of bleeding caused by urinary tract infection can be made. It is recommended to give anti-infection treatment and observe the improvement of blood flow.2. Urinary system stones, such as bladder stones and urethral stones, can show symptoms of urinary frequency, urinary urgency and hematuria in the naked eye, especially when there is effort to urinate or interruption of urination. Further ultrasound examination of the urinary system is needed to understand whether there are stones in the urinary system.3. Tumors of the urinary system can also appear as flesh-eye hematuria, and there is no obvious pain at first, but when combined with infection, urinary frequency, urinary urgency and painful urination can occur. It is recommended to perform ultrasound and CT examination of the urinary system to rule out the presence of related diseases.