Phimosis refers to the narrow opening of the foreskin, so that the foreskin cannot be turned over to reveal the head of the penis. There are two types of phimosis, congenital and acquired. Congenital prepuce can be seen in every normal newborn and infant. When a child is born, the foreskin and the head of the penis adhere to each other. After a few months, the adhesions are gradually absorbed and the foreskin and the head of the penis are separated. By the age of 3 to 4 years old, due to the growth of the penis and the head of the penis, the penis becomes erect, the foreskin can retreat upward on its own, and the head of the penis can be revealed by turning out the foreskin. Circumcision is a normal phenomenon in children and is not pathological. Acquired prepuce refers to the injury of the foreskin and penis head secondary to the circumcision of the penis head and foreskin and penis head, so that the foreskin mouth has scar contracture formation, loss of normal elasticity and expansion ability, resulting in the penis head can not be revealed. It is often accompanied by narrowing of the urethral opening. This kind of prepuce will not heal on its own. Clinical manifestations】 In cases of narrow foreskin, there are difficulties in urination, thin urine line and foreskin bulging. Severe cases can cause ulceration or stone formation on the foreskin and head of the penis. The accumulated foreskin scale is milky white and bean curd-like. Some foreskin scale is as big as a soybean and accumulates at the coronal groove of the head of the penis, with a small white lump across the foreskin, which is often mistaken for a tumor by parents and seen by the doctor. The foreskin scale can induce foreskin inflammation of the head of the penis. In acute inflammation, the mucous membrane of the penis head and foreskin is moist and red and can produce purulent discharge. Children have pain and uneasiness, foreskin edema, and sometimes acute urinary retention. Repeated episodes of foreskin inflammation of the head of the penis can lead to foreskin hyperplasia, hypertrophy, and scar formation. Urodynamic abnormalities have been reported in children with prepuce, manifesting as an unstable bladder. 【Treatment】 For congenital prepuce in infancy, the foreskin can be turned up repeatedly on a trial basis in order to expand the foreskin opening. If the glans is still not revealed after the age of 3, circumcision can be performed at an optional date. Patients with acquired circumcision need to be circumcised because of the fibrous narrow ring at the mouth of the foreskin.