Abnormal uterine bleeding is clinically diagnosed based on history, gynecological examination and other auxiliary tests such as endocrine testing, ultrasound, and diagnostic scraping, but it is influenced by many factors. ① Taking medical history, gynecological examination and clinical experience of doctors are closely related. ② Auxiliary examinations also have limitations, for example, ultrasound is highly sensitive to endometrial mass lesions, but cannot identify small endometrial lesions; diagnostic scraping is often performed by physician’s experience or/and sensation, which often has a high rate of missed diagnosis. In contrast, the diagnostic and therapeutic OCS is a branch of gynecology that has developed very rapidly in recent years. High-resolution OCS can not only detect gross uterine lesions, such as polyps, myomas, malformations, adhesions, foreign bodies, etc., but also show small tissue variants, such as limited endometrial thickening, strawberry-like glandular orifice and vascular anomalies, etc. Especially, OCS localization biopsy can confirm the etiology of abnormal uterine bleeding. The data in this paper showed that the compliance rate between diagnosis and pathological tissue diagnosis by official cavity microscopy was 95%, among which the compliance rate of uterine fibroids and incomplete abortion was 100 %, while the compliance rate between clinical diagnosis and pathological diagnosis was 78%, among which the compliance rate of endometrial polyps was 50%, endometrial hyperplasia was 66%, and 2 cases of endometrial cancer were not diagnosed in time, which indicates that official cavity microscopy diagnosis can be an accurate and credible method to diagnose intrauterine diseases. In addition to the accurate description of the site and morphological characteristics of the lesion, the biggest advantage of the examination is that the material is taken or scraped under direct vision, which greatly improves the accuracy of the diagnosis of intrauterine diseases and makes up for the misdiagnosis and missed diagnosis caused by blind scraping. Although it is highly sensitive in the diagnosis of abnormal intrauterine bleeding, it has limitations in the diagnosis of some diseases, especially endometrial hyperplasia which is easily confused with normal late secretory endometrium. In this paper, there were two cases of misdiagnosis of hyperplastic endometrium as secretory endometrium: there were also two cases of endometrial polyps that were misdiagnosed because they had been scraped outside the hospital before the official hysteroscopy, resulting in changes in the surface morphology of the polyps. Therefore, we believe that although hysteroscopic diagnosis cannot replace pathological diagnosis, it has the tendency to gradually replace traditional scraping.