Black triangle is common phenomenon in our dental clinical treatment, the etiology, diagnosis and treatment of which involving periodontics, prosthodontics and orthodontics. During the dental treatment, we should strengthen the understanding, pay attention to multidisciplinary cooperation, in order to prevent the happening of black triangle effectively. As the increasing of esthetic consciousness, patients put a high demanding on orthodontic treatment. The occurrence of black triangle after orthodontic therapy would not only be unesthetic, but also adversely affect the health of periodontium, occlusal relationship and stability of teeth arrangement. In this article, the prevalence of anterior black triangle after orthodontic treatment, risk factors, diagnosis, treatment and prevention were reviewed, in order to provide a reference for the orthodontic clinical.