Cervical intraepithelial neoplasia (CIN) is a collective term for a group of precancerous lesions closely related to cervical invasive carcinoma, including cervical atypical hyperplasia and cervical carcinoma in situ, reflecting the continuous developmental process in cervical carcinogenesis, i.e. a series of pathological changes from cervical atypical hyperplasia (mild → moderate → severe) → carcinoma in situ → early invasive carcinoma → invasive carcinoma. Screening for cervical cancer and treatment of precancerous lesions reduce the occurrence of cervical cancer. The peak age of CIN is 30-39 years, and the average age of carcinoma in situ is 35-42 years. Human papillomavirus (HPV) infection is associated with the occurrence of cervical precancerous lesions, and HPV infection as a specific type of sexually transmitted disease is the cause of cervical intraepithelial neoplasia. 26 and other 8 types are low-risk types. CIN Ⅲ 80% are HPV16, 18 type infection. CIN is also divided into three levels according to the degree of cell heterotypy: ① CIN grade I: mild atypical hyperplasia, undifferentiated cells limited to the deep epithelial layer (lower 1/3); ② CIN grade II: moderate atypical hyperplasia, undifferentiated cells limited to the deep epithelial layer (lower 2/3). CIN grade III: severe atypical hyperplasia and carcinoma in situ, with undifferentiated cells exceeding 2/3 of the epithelial layer or even reaching the whole layer, but without interstitial infiltration. there are usually no obvious symptoms and signs of CIN, and some of them have manifestations of chronic cervicitis such as increased leucorrhea, leucorrhea with blood, contact bleeding and congestion, erosion and polyps. Cervical conization is a traditional and reliable diagnostic and therapeutic method for highly cervical intraepithelial neoplasia. The indications for cold knife conization are: (1) multiple positive cytology with normal colposcopy or not all transformation zone visible or negative colposcopic biopsy and ECC; (2) inconsistency between cytology report and colposcopic localization biopsy or cervical scraping results; (3) suspected early infiltration on VIA or colposcopic biopsy; (4) CIN lesions grade II-III (extending into the cervical canal); (5) suspected adenocarcinoma. Clinical or colposcopic examination is a contraindication to surgery for those with clear invasive carcinoma . In the clinical management of CIN, it is not possible to accurately determine whether there is infiltration in the interstitium because multi-point biopsies are often limited and superficial. Relying on colposcopic biopsy alone may result in underdiagnosis of some CIN, and some invasive cancers may be missed. The cervical loop circumcision and the loop of the migrating zone can affect the pathological diagnosis of the cut edge because of the thermal effect. In addition, the recurrence rate of LEEP for in situ cancer is high, and it is only suitable for moderate atypical hyperplasia and not for in situ cancer treatment. The scope and depth of lesion excision by cold knife conization of the uterine cervix are sufficient to provide reliable and sufficient biopsies for the diagnosis of CIN and early invasive carcinoma of the uterine cervix, thus ensuring the accuracy of diagnosis. However, intraoperative and postoperative bleeding and the difficulty of suturing technique have been an obstacle to the development of this technique. Our hospital adopts hysteroscopic electrocoagulation to stop bleeding and adjunctive cold knife conization to treat highly cervical intraepithelial neoplasia, which not only continues the characteristics of traditional cold knife conization without interfering with pathological diagnosis, but also utilizes electrothermal and electroradiative effects on the trauma base and surrounding tissues to reduce the occurrence of bleeding and infection, as well as further electrocoagulation of the cut edge to reduce residual and recurrence. Regular follow-up after CIN remains necessary up to the age of 75 years. If necessary, the uterus is removed.