Abnormal uterine bleeding refers to abnormal bleeding originating from the uterine cavity that is inconsistent with any 1 of the normal menstrual cycle frequency, regularity, period length, or period bleeding volume, and is a common clinical symptom in women. A large proportion of patients with this symptom as the main complaint in the clinical work of gynecological endocrinology. However, the diagnosis and treatment of abnormal uterine bleeding in China is still facing many problems. Although the International Federation of Obstetrics and Gynecology published the “Consensus on terms and definitions related to normal and abnormal uterine bleeding” in 2007, followed by the “New classification system for the etiology of abnormal uterine bleeding in women of childbearing age: PALM-COEIN system” in 2011, the domestic definition of AUB is still very limited. “However, there are still many shortcomings in the definition and treatment of AUB in China. The new classification system of etiology: PALM-COEIN, classifies AUB etiology into 9 categories and sorts out the process of AUB etiology diagnosis. PALM refers to structural changes that can be diagnosed by imaging and/or histopathological methods, including polyps, adenomyosis, uterine smooth muscle tumors, endometrial malignancies and atypical hyperplasia, while COEIN has no structural changes, including systemic coagulation-related diseases, ovulation disorders, endometrial local abnormalities, medical origin and unclassified AUB. The guidelines describe the corresponding clinical presentation, diagnosis and management according to the classification system, which is a good reference for clinicians in the diagnosis and management of abnormal uterine bleeding.