Trichotillomania(TTM), also known as hair pulling disorder or hair pulling syndrome, is characterized by the repeated and uncontrollable urge to pull one′s own hair which results in hair loss, causing significant functional impairment or psychological distress.Its diagnosis mainly relies on detailed medical history collection, skin examination, and auxiliary examinations.It should be distinguished from physical diseases (alopecia areata, androgenetic alopecia, and hair loss caused by other medical reasons) and other mental illnesses(autism spectrum disorder, other obsessive-compulsive and related disorders, schizophrenia or other primary psychiatric disorders, etc.) that cause hair loss. The treatment of TTM includes medication therapy, psychological and behavioral therapy, physical therapy. However, some therapies are merely based on case reports. Multi-center, randomized controlled trials should be conducted to further validate efficacy, and provide a scientific basis for optimizing the treatment of TTM. This paper systematically reviews the conceptual changes and diagnostic classification, epidemiology, pathogenesis, clinical manifestations, diagnosis and differential diagnosis, comorbidities and treatment of TTM, providing a reference for clinical diagnosis and treatment.