The appearance of a brown strip on the glans is mainly considered to be related to external injury, pigmentation and inflammatory effects. 1. external injury: such as underwear is too tight, resulting in the glans being compressed, or the glans has been subjected to other external injuries, may lead to the appearance of brown stripes on the glans. 2. Hyperpigmentation: localized hyperpigmentation of the glans may also lead to the appearance of brown stripes or patches on the glans. 3. Inflammatory effects: Diseases such as plasma cellular priapism may lead to the appearance of dark red patches on the affected area. The same may occur if timely intervention is not made. The appearance of this phenomenon may also be related to other factors. It is recommended that men should seek medical attention to confirm the diagnosis and target treatment to the cause.