Endometriosis, one of the common gynecologic diseases in women of reproductive age, may cause dysmenorrhea and infertility. Serum CA-125 is a valuable tumor biomarker in the evaluation of treatment and follow-up of recurrence in patients with endometriosis and initially elevated CA-125 level. This case is a 31 y/o female who was diagnosed as? endometriosis with dysmenorrhea, yellowish vaginal discharge, and elevated CA-125 level. According to TCM’s theory, the patient was diagnosed with Qi Stagnancy in Liver and the blockade of damp-heat and static blood. After the prescription of Longdan Xiegan Tang and Guizhi Fuling Wan, which was aimed to relieving Qi stagnancy in Liver, clearing damp-heat, and promoting blood circulation, the patient’s symptoms and CA-125 level has improved. However, when the dosage of Longdan Xiegan Tang decreased, the patient’s dysmenorrhea became severe, and CA-125 level elevated again. Therefore, we deduced that the symptoms of blockade of damp-heat and static blood could not be improved, so the CA-125 level elevated again when the dosage of Longdan Xiegan Tang being reduced to 3g/day. But it is still necessary to observe more cases and studies for actual conclusion.