There are many causes of infertility in patients who come to our center, and many of them have been mentioned in previous public articles, so today we will talk specifically about endometriosis. If the active endometrial tissue (glandular and mesenchymal) is ectopic and grows outside the uterine cavity, recurrent cyclic bleeding occurs, and disease develops and symptoms appear, it is called endometriosis. Ectopic sites Ectopic endometrium can invade any part of the body, but most of them are located in the pelvic cavity, with the ovaries and the uterosacral ligament being the most common. Since the concept of endometriosis was described, there have been many different theories about its pathogenesis, but the leading theory is the endometrial implantation theory. Endometrial implantation means that during menstruation, menstrual blood can flow back into the fallopian tubes from the uterine cavity and enter the pelvis through the umbilical end. The endometrial fragments mixed with menstrual blood are planted in the pelvis, abdominal organs and peritoneal surfaces, where they continue to grow and spread, resulting in the formation of endometriosis. A large percentage of patients with endometriosis seen at our center are ovarian chocolate cysts, referred to as “coeliac disease”. (1) Main clinical manifestations (1) Dysmenorrhea: secondary, progressive dysmenorrhea, more obvious when combined with lesions of the rectal fossa and the uterosacral ligament, with a feeling of anal swelling, or painful intercourse. (2) Menstrual disorders: increased menstrual flow, prolonged menstrual period, and incomplete menstruation. (3) Infertility. (1) History: women of childbearing age with secondary, progressive dysmenorrhea and history of infertility; (2) Gynecological examination: poorly mobile cystic masses in the adnexal region; (3) Ancillary tests: ultrasound, blood CA125; laparoscopy is required to confirm the diagnosis. The overall treatment principle is based on the patient’s age, the severity of symptoms, the extent of the lesion, and the requirements for fertility. (1) For small chocolate cysts that do not affect ovarian function or the pregnancy process, they can be left untreated and normal ovulation promotion, egg retrieval, fertilization and embryo transfer can be performed; (2) For patients with poor ovarian function, in order to shorten the waiting time, capture the available eggs and avoid further damage to the ovaries during surgery, we can first perform ovulation promotion, egg retrieval and fertilization. (2) For patients with poor ovarian function, in order to shorten the waiting time, capture the available eggs and avoid further damage to the ovaries, ovulation, egg retrieval, fertilization, embryo freezing and embryo resuscitation and transfer can be performed first; (3) The pregnancy rate after surgery is 40%-70%, but the recurrence rate after such surgery is as high as 15%, so timely pregnancy after surgery is especially important for the treatment of such patients.