The causes of premature ejaculation are as follows:1. The foreskin of patients with prepuce is hypertrophied and fibrotic due to chronic inflammation, and the outer opening of the foreskin is narrowed, which leads to premature ejaculation due to erection pain when the penis is erected.2. The glans of patients with prepuce is too sensitive, which leads to premature ejaculation due to sensitivity when the penis is inserted into the vagina.3. There is a large amount of bacteria in the inner plate of the foreskin between the foreskin and the head of the penis in the patients with prepuce and the retrograde infection of bacteria can complicate urethritis and prostatitis, leading to swelling and loosening of the opening of the spermatorrhoea. The bacterial retrograde infection can be complicated by urethritis and prostatitis, leading to inflammatory edema of the seminal mound and relaxation of the opening, so the symptoms of premature ejaculation appear. For the treatment of premature ejaculation caused by the prepuce, the main line of circumcision, and then symptomatic treatment.