Overview: Cervical intraepithelial neoplasia (CIN) is a group of precancerous lesions closely associated with cervical infiltration, which reflects a continuum in the development of cervical cancer. Human papillomavirus (HPV) infection is the most important risk factor in the development of CIN. CIN is also associated with sexual disorders, smoking, premature sex, sexually transmitted diseases, low economic status, oral contraceptives and immunosuppression. HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56 or 58 are high-risk types. CIN has two different outcomes, one in which the lesion regresses spontaneously and rarely progresses to invasive cancer, and the other in which the lesion has cancerous potential and may progress to invasive cancer. cIN often occurs in women aged 25-35 years, whereas cervical cancer is most often seen in women over 40 years of age. Clinical manifestations: Cervical squamous intraepithelial neoplasia has no specific symptoms. Occasionally, there is increased vaginal discharge with or without foul odor. There may also be contact bleeding, which occurs after sexual intercourse or gynecological examination. Signs may be without obvious lesions, and the cervix may be smooth or may only show local erythema, white epithelium, or cervical erosion. Treatment: CIN management should be individualized, taking into account disease status (CIN grade, site, extent, HPV-DNA testing), patient condition (age, marital status, follow-up conditions) and technical factors. Low-grade cervical intraepithelial neoplasia (CIN I): about 60% of CIN I may disappear spontaneously; if the lesion develops or persists for 2 years, treatment is required and cervical conization, such as cervical loop electrosurgery, is recommended. High-grade cervical intraepithelial neoplasia (CIN II and CIN III): about 20% of CIN II will develop into CIN III and 5% into invasive cancer, so all CIN II and CIN III need to be treated. Cervical conization (LEEP knife or cold knife) is recommended. Total hysterectomy is also feasible for CIN III diagnosed by cervical conization, older age, no fertility requirements, and combined with other surgical indications for benign gynecological diseases.