The reason for the pain in the abdomen after urination: 1, cystitis urethritis, diffuse inflammation of the bladder can occur in the small abdomen pain, in the state of holding urine or bladder emptying can appear pain, need further urine routine examination, often accompanied by urinary urgency, urinary pain or red urine and other changes. 2, bladder stones, stones with the flow of urine to stimulate the bladder mucosa can produce small abdominal pain, sometimes stones blocking the urethral orifice can also appear pain. Sometimes stones blocking the urethra can also lead to interruption of urination, and ultrasound examination of the urinary system is needed to rule out the presence of stones. 3. Bladder tumors can also cause pain in the bladder area after urination, and can also be accompanied by obvious bleeding and red urine. If the bladder tumor further increases in size, it can also cause frequent urination or persistent small abdominal pain, so it is recommended to go to the hospital for an ultrasound examination of the urinary system to rule out.