The circle around the urethra is red, then the possible causes: first, due to urethral infection. When suffering from urethritis can appear urinary frequency, urinary urgency, painful urination, and accompanied by a circle of red urethral orifice, then there can be a mild swelling of the urethral orifice, accompanied by increased pain when urinating, etc., need to carry out routine urine examination to further confirm the diagnosis. Second, local irritation. For example, excessive friction or excessive masturbation can lead to enhanced local mechanical stimulation and mucosal damage resulting in redness around the urethra. It can also be seen after circumcision when the glans repeatedly rubs against the underwear, showing a short period of redness, and the redness can gradually return to normal after stopping the relevant frictional stimulation. Third, when suffering from glansitis can appear red around the urethra, accompanied by changes such as redness and swelling in other parts of the glans, but also with local exudation or secretions, the need for local pathogenic examination to use topical drugs to anti-infection treatment.