The possible reasons for difficulty in urination even after removal of the urethral catheter are as follows: 1. The primary disease is not removed, such as urethral stricture or prostatic hyperplasia symptoms, etc. The obstructive disease has been lifted through the urethral catheter during the retention of the urethral catheter, and urine can be drained out smoothly. However, if there is no further treatment for the cause, such as medication and surgery for prostate, urethral dilatation or surgery for urethral stricture, the original disease still exists after removal of the urethral tube, still causing urethral stricture or obstruction, so it is still impossible to urinate. 2, after removal of the tube combined with congestion and edema of the urethral mucosa or combined with infection, the resistance in the urethra increases, and the bladder pressure has to overcome the excessive urethral 3.The bladder function is not trained before the catheter is removed, for example, the catheter is continuously opened during the catheterization period, resulting in weak contraction of the bladder forcing muscle, and after the catheter is removed, the contraction of the bladder forcing muscle is not strong enough to expel the urine from the bladder through muscle contraction and squeezing.