Cervical cancer is usually preceded by precancerous lesions for a long time, so cervical cytology can detect abnormalities early and treat them promptly. Cervical cells become poorly differentiated, disorganized, and have abnormal nuclei, resulting in cervical intraepithelial neoplasia (CIN). Depending on the extent of cervical heterogeneous cells occupying the cervical epithelial layer, CIN is classified as grade I, II, or III. Further studies have revealed that CIN is not a single continuous lesion of varying degrees, but can be divided into two types of lesions with distinctly different clinicopathological processes: low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL); LSIL corresponds to CINI grade, while HSIL includes CIN grades II and III. LSIL mostly resolves spontaneously and rarely progresses. However, HSIL often has high-risk HPV infection, which does not easily regress spontaneously and is more likely to develop into invasive carcinoma. Because of the differences in the progression of these two types of lesions, the clinical treatment options for both are significantly different. Physicians diagnosing and treating cervical disease follow a complex set of flow charts to make different management of different lesions. In the case of HSIL, which is prone to develop into cervical cancer, it should be taken seriously enough to undergo further tests to clarify the diagnosis and be treated promptly.