OBJECTIVE： To discuss clinical efficacy and safety of leuprolide acetate in the treatment of endometriosis. METHODS： 66 endometriosis patients were divided into observation group （37 cases） and control group （29 cases） according to random number table method. Observation group was treated with Leuprolide acetate microsphere for injection， 3.75 mg/time， on the upper arm， abdomen or buttocks since the first-fifth day of menstrual cycle （administration time was available at hysterectomized patients disposal）， and then every 4 weeks； one administration was recognized as a treatment course. Control group was treated with Ethinyl estradiol cyproterone tablet orally， 1 tablets per day for 3 weeks， one week drug withdrawal， as a treatment course. 2 groups were given 3-5 courses of treatment according to their tolerance or the improvement of clinical symptoms. The improvement of clinical symptoms were compared between 2 groups， and the levels of FSH， LH and E2 were compared before and after treatment； the occurrence of ADR and the time of the return of menses were recorded. RESULTS： 2 patients in observation group and 1 patient in control group withdrew from the test. After treatment， total effective rate was 97.14％ in observation group， which was significantly higher than 75.00％ in control group， with statistical significance （P＜0.05）. Before treatment， there was no statistical significance in the levels of FSH， LH and E2 between 2 groups （P＞0.05）. After treatment， the levels of FSH， LH and E2 were decreased significantly， and the observation group was more significant than the control group， with statistical significance （P＜0.05）. Total incidence of ADR was 20.00％ in observation group， compared to control group （21.42％）， there was no statistical significance （P＞0.05）. The time of the return of menses in observation group was （89.75±3.34） d after drug withdrawal， compared to control group [（88.46±2.94）d]， there was no statistical significance （P＞0.05）. CONCLUSIONS： Leuprolide acetate can effectively improve clinical symptoms of patients with endometriosis， and reduce the levels of FSH， LH and E2 with slight ADR， and it doesn’t influence the time of the return of menses.