Hysteroscopy is a new, minimally invasive gynecological diagnosis and treatment technology. Hysteroscopy not only determines the site, size, appearance and scope of the presence of the lesion, but also provides meticulous observation of the tissue structure on the surface of the lesion, and takes or locates the scraping under direct vision, which greatly improves the accuracy of the diagnosis of diseases in the uterine cavity and updates and makes up for the shortcomings of traditional treatment methods. 1. Clarify the uterine etiology of infertility:It helps to understand the causes of habitual abortion, such as relaxation of the endocervix, old lacerations and defects of the cervical canal, uterine malformation, uterine adhesions, etc. The proportion of infertility patients with abnormalities under hysteroscopy is high; combined hysteroscopy and laparoscopy can provide a more comprehensive understanding of the causes of infertility and can give corresponding treatment. 2.Insertion under direct view of hysteroscopy and injection of fluid under pressure can clearly diagnose tubal obstruction and unblock the fallopian tubes: tubal obstruction is an important cause of female infertility. The mature application of hysteroscopic direct vision intubation with pressure injection has enabled some patients with tubal infertility to be effectively diagnosed and treated and to successfully obtain intrauterine pregnancy, with a success rate of more than 80%. 3. Separation of uterine adhesions: Hysteroscopy can not only classify the degree of adhesions under direct vision, but also separate the adhesions without hurting the normal mucosa, which is safer and more effective than blind separation. The rate of normal menstruation restoration is high, thus improving the conception rate. 4.Removal of residual pregnancy and birth control device: the residual of small amount of pregnancy during multiple abortions or the residual bone fragments after scraping of larger months of pregnancy can lead to secondary infertility; there are also abnormal uterine bleeding caused by the fracture of the birth control device remaining in the uterine cavity, which affects conception. They can be found and removed under direct hysteroscopic view. 5. Removal of mid-uterine diaphragm: Mid-uterine diaphragm is a malformation of the uterus, which is prone to miscarriage, embryonic abortion, premature birth and fetal malposition. After the diagnosis is confirmed under hysteroscopy, the diaphragm can be removed under microscopic surgery. This greatly reduces the damage to the uterus compared to traditional surgical methods. 6.Endometrial polyp and submucosal fibroid removal: hysteroscopic surgery makes the removal of submucosal fibroids by cervical route a reality. 7. Diagnostic examination before IVF embryo transfer: hysteroscopy should be performed in every case where pregnancy cannot be achieved after transfer of high quality embryos, and it is also recommended to do hysteroscopy routinely before.