Abstract：Objective：To observe the clinical effect of modified Buyang Huanwu tang for endometriosis. Methods：A total of 103 cases of patients with endometriosis were selected and divided into the observation group and the control group according to the random number table method，with 52 and 51 cases in each group respectively. The control group was given Sanjie Zhentong capsules， and the observation group was treated with modified Buyang Huanwu tang. Before and after treatment， dysmenorrhea scores， Chinese medicine syndrome scores， levels of carbohydrate antigen 125(CA125)， interleukin- 8(IL- 8) and tumor necrosis factor- α(TNF- α) in serum and changes of pelvic lumps in the two groups were compared. Results：The total effective rate was 94.23% in the observation group，higher than that of 58.82% in the control group， the difference being significant(P＜0.05). After treatment， dysmenorrhea scores and Chinese medicine syndrome scores in the two groups were decreased when compared with those before treatment， and the dysmenorrhea score and Chinese medicine syndrome score in the observation group were lower than those in the control group，the difference being significant(P＜0.05). After treatment， the levels of CA125， IL- 8 and TNF- α and the diameter of pelvic lumps in the two groups were decreased when compared with those before treatment，and the levels of CA125，IL- 8 and TNF- α and the diameter of pelvic lumps in the observation group were lower than those in the control group，differences being significant (P＜0.05). Conclusion：Modified Buyang Huanwu tang has a significant curative effect in treating endometriosis，which can effectively relieve dysmenorrhea symptoms of patients，reduce pelvic lumps，decrease levels of tumor markers and improve immunity of patients.