Blood in the urine of kidney stones is usually not too dangerous, but it may be dangerous if the stone becomes embedded. Blood in urine is a relatively common phenomenon of kidney stones, which may be caused by mucosal bleeding due to repeated friction between the stone and the renal pelvic mucosa for a long time, or it may be caused by hematuria due to damage to the ureteral mucosa and urethral mucosa caused by the stone passing through the ureteral and urethral walls during the process of discharging, most of them are not dangerous, but they still need to be treated in time. However, some patients may have ureteral impaction or urethral impaction during the process of kidney stone expulsion, which may lead to ureteral blockage or urethral blockage, and may cause severe pain, high fever, infectious shock, urinary retention and other complications, which are still dangerous. Kidney stones with blood in urine need to go to the hospital in time and be treated under the guidance of doctors.