Bloody urine during male coitus may be an injury to the mucous membrane of the penis, or it may be caused by urinary stones, urinary tract infections, urinary tract tumors and other reasons. 1. If the sex life is too strenuous or long time erection, it may lead to the damage of the urethral mucosa, and when urinating, it can lead to hematuria, which is mostly accompanied by the symptom of urinary pain. 2. Infection of the urinary system can appear frequent urination, urinary urgency, urinary pain, urethral mucosa because of inflammation leads to erosion, can also appear hematuria. 3. If the sex life is too strenuous, can lead to the movement of urinary stones, the process of movement cuts the mucous membrane of the urethra can also lead to blood in the urine. 3. Urinary system tumor due to the tumor is rich in blood vessels, easy to break bleeding, can also appear blood in the urine. Therefore, if there is blood in the urine after sex, it is recommended to go to the hospital for timely consultation to find out the specific cause of the disease and then give appropriate treatment.