Urethral stricture is a common disease of the urinary system, mostly seen in men. It is common to have congenital urethral strictures such as seminoma hypertrophy, urethral valves, congenital urethral external stenosis, congenital narrowing of the urethral canal, etc. Inflammatory urethral strictures are often due to urethral canal infection and injury, and traumatic urethral strictures are mostly due to improper treatment at the initial stage of injury. What are the causes of urethral stricture? 1, traumatic urethral stricture: the most common, due to serious urethral injury, improper or untimely initial treatment. Pathologically the degree, depth and length of the stricture vary greatly, usually only one stricture, gonorrheal stricture may be multiple strictures, the stricture may be secondary to infection, the formation of urethral diverticulum, periurethritis, prostate or epididymal testosteritis. Due to the long-term obstruction of urinary flow cannot be lifted, it may eventually lead to hydronephrosis and uremia due to kidney function impairment. 2, inflammatory urethral stricture: such as gonorrheal urethral stricture, in addition to indwelling catheter can also cause urethral stricture. 3, congenital urethral stricture: such as urethral stenosis, urethral valve, etc.