Intraepithelial neoplasia occurs not only in the cervix, but also in the vulva and vagina. However, CIN (cervical intraepithelial neoplasia) is more common in women. Cervical cancer as we know it has a long precancerous stage called cervical intraepithelial neoplasia (CIN). In 1973, Richart proposed a morphological “trichotomy” for the pathological diagnosis of cervical intraepithelial neoplasia based on the proportion of heterogeneous cells in the squamous epithelium as a grading criterion. CIN 1, CIN 2, and CIN 3. All levels of CIN can have a tendency to develop into invasive carcinoma, and the higher the grade, the greater the chance of developing into invasive carcinoma. In 2012, the United States proposed a dichotomous approach to cervical intraepithelial neoplasia pathology, with CIN 1 classified as low-grade squamous epithelial lesion (LSIL) and CIN 2/3 classified as high-grade squamous epithelial lesion (HSIL). Using a nomenclature that unifies cytologic and histologic diagnostic terms will facilitate communication between pathologists and clinicians. CIN 1 tends to regress spontaneously in 60-85% of cases, so treatment of CIN 1 tends to be conservative, i.e., regular review on an outpatient basis; CIN 2 also has the potential to regress, but may progress to CIN 3. Therefore, CIN 2 can be treated conservatively or with cervical conization, depending on the patient’s age, whether the patient is fertile or not, and the patient’s own wishes. If CIN 3 is diagnosed, cervical conization is basically performed. Of course, regular follow-up is needed after surgery, i.e., hospital visits every 6 months to 1 year.