Objective: To evaluate the effectiveness of ultra-long protocol on reproductive and controlled ovarian hyperstimulation outcome in in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) in infertile women with endometriosis versus long protocol. Methods: We retrieved articles without language restrictions in the Elsevier ScienceDirect, Embase, Medline, PubMed, Web of Science, China National Knowledge Infrastructure, Wan Fang Data Knowledge Service Platform and China Science and Technology Journal Database from inception to August 2020. RCTs including the comparison of reproductive outcome of infertile patients with endometriosis who underwent ultra-long protocol and long protocol were selected. Data extraction was conducted using RevMan 5.3. Results: A total of nine RCTs in compliance with the standard literature were included. This meta-analysis suggested that ultra-long protocol with a 3-month downregulation could increase clinical pregnancy rate of infertile women with endometriosis (RR=1.31, 95% CI:1.11 similar to 1.55, P = 0.002) versus long protocol. However, subgroup analysis found the different protocol provided no significant difference in improving clinical outcomes in patients with different disease stage of endometriosis. Conclusion: The ultra-long protocol could improve the clinical pregnancy rate of infertile women with endometriosis compared with long protocol with a 3-month downregulation. And ultra-long protocol could be effective to increase the ongoing pregnancy rate compared to long-protocol. But, the efficacy of ultra-long protocol is not different between early and advanced stage of endometriosis.