Surgery for 100 ml of residual urine cannot be generalized, but should be combined with the presence of prostate disease, or the presence of urethral stenosis, as well as whether it is postoperative and other circumstances. 1. prostate disease: generally prostate disease caused by residual urine more than 50 ml or more, is the indication of prostatic hyperplasia surgery, and residual urine for 100 ml, it is recommended to carry out surgical treatment, to restore the smoothness of the urethra. 2. Urethral stenosis: If urinary retention is caused by urethral stenosis, urethral dilatation or other surgical treatments are needed to relieve urinary retention. 3. Post-operative: If it is after uterine surgery for women or rectal surgery for men, residual urine can occur after surgery, in which case a catheter can be left in place to catheterize the urine and the pelvic floor muscles can be functionally exercised. Therefore, if the residual urine is 100 ml, it is necessary to treat the cause of the residual urine accordingly.