Objective:To investigate the effect of different down-regulation protocols on the outcome of in vitro fertilization-embry-otransfer in patients with endometriosis. Methods:Clinical data of 108 patients with endometriosis who underwent in vitro fertilization-embryo transfer in the reproductive center of the Third Affiliated Hospital of Zhengzhou University from January 2010 to December 2012 were analyzed. According to the different down-regulation protocols,patients were divided into two groups:prolonged therapy group(n=33) and super prolonged therapy group(n=75). Outcome of assisted reproduction between the two groups was analyzed. Results:There was no obvious difference in patients’ age,infertility duration,basic of follicle-stimulation hornone,luteinizing hormone and estradion levels(P >0.05). Total duration and dosage of gonadotropin were obvious higher in super prolonged therapy than in pro-longed therapy group,but the number of oocytes and cleavage,number of transferable embryo and number of high quality embryo were fewer in super prolonged therapy than in prolonged therapy group(P<0.05). Clinical pregnancy rate and embryo implantantion rate were higher in super prolonged therapy than in prolonged therapy group(P<0.05). Conclusions:Use of super prolonged protocol regulation can improve embryo implantantion rate and pregnancy rate for patients with endometriosis at Ⅲ-Ⅳ stage.