Hysteroscopy is the gold standard for the diagnosis of intrauterine lesions. Hysteroscopy should be considered in the following cases 1. abnormal uterine bleeding: such as excessive and frequent menstruation, prolonged menstruation, irregular uterine bleeding, bleeding after menopause, uterine bleeding around menopause, etc.; 2. etiological examination of infertility; 3. occupying lesions in the cervical canal and uterine cavity: submucosal fibroids, intermural endometrium fibroids, polyps, etc. 4. abnormal intrauterine devices; 5. intrauterine foreign body localization and trial extraction; 6. uterine malformation; 7. uterine cavity Imaging abnormalities; 8, decreased menstrual flow, uterine cavity and cervical adhesions; 9, vaginal foreign body or drainage; 10, screening for indications for hysteroscopic surgery; 11, endometrial changes caused by special drugs; 12, evaluation related to post hysteroscopic surgery.