Abstract： Endometriosis is a challenging gynecological condition， with dysmenorrhea being its most typical symptom. Professor XIANG Dongfang， in clinical practice， applies the classic theory of Chinese medicine formulas advocated by the renowned expert XU Jiadong. This theory is used to understand dysmenorrhea in endometriosis from the perspective of the pathogenesis of diseases similar to reverting yin syndrome and to guide syndrome differentiation and treatment. It is believed that the disease primarily affects the three yin meridians（ greater yin，lesser yin，and reverting yin），with a focus on the reverting yin meridian. In treatment，both exterior and interior pathogenic factors，cold and heat，and deficiency and excess should be considered. Emphasis is placed on warming and supplementing，and the use of bitter and cold purgatives should be avoided when there is heat. Medications that activate blood circulation are commonly used， but aggressive purgation is prohibited. Prescriptions such as Bupleurum-based formulas， Peucedanum-based formulas， and heart-draining based formulas are frequently applied， achieving satisfactory therapeutic effects.