Evaluation of abnormal uterine bleeding: including abnormal bleeding that occurs during the fertile, peri-menopausal and post-menopausal periods. Evaluation of infertility: including routine diagnosis of infertility, abnormal uterine tubal iodine oil imaging, evaluation of the intrauterine environment prior to performing in vitro fertilization and recurrent spontaneous abortion. Evaluation of abnormal intrauterine acoustic imaging, hysteroscopy can be used to confirm and evaluate the localization of intrauterine lesions, and biopsy and cytology can be performed on suspicious areas. Localization of foreign bodies: including lost IUDs and displaced bands at the endocervical os. 2.Postoperative evaluation: Re-examination after all hysteroscopic procedures, evaluation of the condition of the uterine cavity, evaluation of postpartum or abortion patients with difficulty in scraping or low menstrual flow, examination of the scar after cesarean section, and review of recurrent bleeding after endometrial removal. 3.Classification of submucosal fibroids and determination of surgical treatment. 4.Evaluation of the endometrium after fibroid embolization. 5.Abnormal vaginal discharge or abnormal uterine aspiration cytology or abnormal endometrial pathology and histology. 6.Staging of endometrial cancer and secondary exploration after non-surgical operation. 7.Secondary dysmenorrhea, persistent bleeding after abortion or failure of abortion removal, prolonged postpartum hemorrhage and residual embryonic material after abortion removal, used to distinguish tubal pregnancy or interstitial pregnancy.