A singular mastoid emissary vein, is a small venous channel without a valve, connecting the sigmoid sinus with either the posterior auricular or the occipital veins. The morphology and shape of the mastoid emissary vein vary from individual to individual. Pulsatile tinnitus has been a hot topic in otology recently, and its incidence is increasing yearly. Meanwhile, with the rapid development of microsurgery, more and more surgeries involving the mastoid region are being performed. Accidental bleeding and embolization due to unintentional injury to the mastoid emissary vein during surgery. Therefore, it is necessary to reveal the true nature of the mastoid emissary vein. This paper discusses the origin, anatomy, and clinical significance of the mastoid emissary vein.