Hysteroscopy is an extremely important step in the modern diagnosis and treatment of infertility, which can directly observe the morphology of the cervical canal, endometrial cavity and bilateral fallopian tube orifices, and take biopsies (for pathological examination) under direct vision; for certain deformities, some uterine adhesions, polyps, forgotten birth control devices or submucosal fibroids with stipe, they can be detached or picked out under the microscope; the carnal changes of the endometrium in secretion period can be observed in detail before the period; when diagnosing tubal occlusion, a tube can be inserted into the tubal opening to inject methylene blue liquid under the uteroscopy, and the smoothness of the tubal passage can be jointly observed through the laparoscopy; when diagnosing tubal occlusion, it can be inserted into the tubal opening to inject methylene blue liquid under the uteroscopy to observe the smoothness of the tubal passage. In the premenstrual period, it can also observe in detail the change of endothelium during the secretion period; in the diagnosis and examination of tubal occlusion, it can be inserted into the tubal opening and injected with the methylene blue liquid under the hysteroscope, and then observe the tubal patency through the combination of laparoscopy; and unilateral tubal insertion and injection has the role of restoration treatment for the mild adhesion of tubal lumen. Hysteroscopy has been introduced for more than 100 years, but it was not until the early 1970s of this century, with the development and application of fiber optics, micro-mechanics and dilatation media, the clinical value of hysteroscopy has been re-embodied. Hysteroscopy is mainly used to investigate the intrauterine causes of abnormal uterine bleeding and primary or secondary infertility. Treatment is used for the localization and removal of intrauterine devices, tubal adhesion, and so on. Hysteroscopy is contraindicated for active uterine bleeding, acute or subacute inflammation of the reproductive tract, recent history of uterine perforation or uterine surgery for those who wish to continue the pregnancy, those who have difficulty in dilating the cervix, and cervical malignancy. The examination time is usually within 5 days after menstruation. After the examination, bed rest and observation for 1 hour, give antibiotics to prevent infection as appropriate, and abstain from sexual intercourse for 2 weeks. Side effects and complications: the possible side effects and complications caused by abortion may also occur after the hysteroscopy, but if it is operated carefully according to the requirements, only a small number of patients complained of vague pain in the lower abdomen after the examination, which is mostly relieved within one hour, and there may be a small amount of vaginal bloody secretion in the second to seventh days after the examination.