Hysteroscopy is an endoscope used for the diagnosis and treatment of diseases of the uterine cavity and cervical canal. The uterine cavity is dilated with a dilatation medium and a cold light source is introduced through the hysteroscope via a light-guided glass fiber bundle and a columnar lens to allow direct visualization or magnification of images of the uterine cavity and cervical canal by an attached camera system and a surveillance screen. Most of the uterine cavity and cervical canal lesions can be diagnosed and treated simultaneously under hysteroscopy. I. Hysteroscopy is both the gold standard for diagnosis, and the minimally invasive technique of choice for treatment of uterine cavity and cervical canal diseases. Xie Feng, Cervical Disease Treatment Center, Obstetrics and Gynecology Hospital of Fudan University I. Who needs hysteroscopy. Hysteroscopy 1. abnormal uterine bleeding; 2. infertility; 3. recurrent miscarriage; 4. ultrasound scan suggesting abnormal occupancy or morphology of the uterine cavity and cervical canal; iodine oil imaging of the uterine tubes reveals abnormal images of the uterine cavity and cervical canal; 5. suspected intrauterine pregnancy, foreign body residue or failed removal or residue of intrauterine device, clarifying whether there is embedded or perforated; 6. vaginal exfoliative cytology reveals cancer cells or suspected cancer cells Except for cervicovaginal source; 7. Staging of endometrial cancer, clarify whether it invades the cervical mucosa; 8. Diagnosis of cervical and vaginal lesions in young girls and virgins; 9. Follow-up after hysteroscopic surgery. Hysteroscopic treatment 1, tubal intubation and lavage (infertility, tubal pregnancy); 2, intra-tubal gamete transplantation (GIFT) via hysteroscopic tubal intubation; 3, endometrial polyp removal; 4, uterine adhesion decomposition; 5, longitudinal septotomy; 6, submucosal myoma removal; 7, uterine foreign body removal; 8, endometrial resection or ablation; 9, cervical canal superfluous excision; 10 Hysteroscopy-guided sterilization; 11. Evaluation of the extent of endometrial cancer or precancerous lesions. Contraindications to hysteroscopy ①absolute contraindications 1, acute and subacute reproductive tract inflammation; 2, severe cardiopulmonary insufficiency. ② Relative contraindications 1. menstrual period and active uterine bleeding; 2. cervical malignancy; 3. recent history of uterine perforation or uterine surgery. The timing of hysteroscopic surgery is generally appropriate within one week after menstruation, when the endometrium is in the proliferative phase, thin and less prone to bleeding, with little mucus secretion and easy to see uterine cavity lesions. Submucosal fibroids or endometrial lesions, heavy menstrual flow or continuous irregular bleeding triggering moderate to severe anemia, it is advisable to stop bleeding and improve anemia as soon as possible. 4. Preparation before hysteroscopy 1. Medical history: Carefully inquire about the patient’s general health and past history, pay attention to any serious heart, lung, liver, kidney and other important organ disorders, except for the possibility of pregnancy in case of irregular menstruation. 2. Physical examination: Routine gynecological examination to exclude acute and subacute inflammation of the reproductive tract, and routine measurement of vital signs. 3. Auxiliary examinations: routine leukological examination including trichomonas, mycobacteria and cleanliness, cervical cytology, blood count, coagulation function, liver and kidney function, fasting glucose, hepatitis markers, syphilis screening, HIV testing, electrocardiogram. In case of combined medical disorders, appropriate tests should be performed. For older patients (65 years old or above), cardiopulmonary function tests should be performed. (1) For some postmenopausal patients with cervical atrophy or a history of cervical surgery causing cervical stenosis that is difficult to dilate, cervical preparation is feasible. (2) For type I or II submucosal fibroids larger than 4 cm in diameter, in order to shrink the fibroids, reduce blood supply, control bleeding, improve anemia, reduce surgical difficulties, and shorten surgical time (2) In order to shrink fibroids, reduce blood supply, control bleeding, improve anemia, reduce surgical difficulties and shorten the operation time, Danazol or GnRH-a drugs can be applied for 3 months. (3) For patients who are to undergo endometrial resection, drugs can be applied to pretreat the endometrium in order to thin the endometrium and improve the success rate of surgery by helping to obtain an effective depth of tissue destruction. The medication is administered in the same way as endometriosis medication.