The urethra is a very important component of the genitourinary system, and there are differences in the length of the urethra between men and women. In female patients, the urethra is congenitally short and straight, with a length of about 5cm. Because of the characteristics of the female urethra, it is clinically easy to cause retrograde infection of bacteria, causing acute inflammation of the bladder and urethra. For men the urethra is longer, the average length of the male urethra is about 20cm, the male urethra has 2 curves, the inferior pubic curve and the anterior pubic curve, divided into the anterior urethra and the posterior urethra, there is the internal urethra, the external urethra, the posterior urethra can be divided into the prostate urethra and the membrane urethra, the anterior urethra can be divided into the bulb urethra and the penile corpus cavernosum urethra. Due to the long urethra, it rarely causes acute cystitis in clinical practice.