Hysteroscopy is the expansion of the uterine cavity using saline and other uterine expansion media, and the hysteroscope is introduced into the uterine cavity for observation through a cold light source such as a fiber-guided beam or lens, which is advanced, safe and less painful, so it is now widely used clinically. What people need to do hysteroscopy, as follows: 1, generally applies to the first abnormal uterine bleeding, such as shortened menstrual cycle, or prolonged period, abnormal blood volume and so on abnormal uterine bleeding; 2, excessive menstrual blood volume, generally more than the patient’s own menstrual volume of 2-3 times, or even more than 2-3 times, you can perform hysteroscopy, to exclude whether there are some endometrial abnormalities, to find out the cause of bleeding as much as possible; to find out the cause of the endometrial abnormalities. 3, endometrial histological diagnosis or cytological diagnosis of abnormalities, considering suspected endometrial cancer or precancerous lesions, hysteroscopy can be used for further sampling; 4, abnormalities seen in the uterine cavity, such as existing uterine adhesions or existing intrauterine occupying lesions, such as uterine fibroids, endometrial polyps, hysteroscopy can also be performed and treatment can be given if necessary; 5, infertility or In patients with infertility or recurrent miscarriage, the purpose of hysteroscopy for infertility is to further assess whether there are any abnormalities in the uterine cavity where the baby lives, and in patients with recurrent miscarriage, hysteroscopy should also be performed to see the morphology of the lower uterine cavity, distribution of endometrial glands, distribution of blood vessels, etc.; 6. Suspected intrauterine foreign bodies, such as broken fetal bones and birth control devices, need to be removed by hysteroscopy.