Cervical cancer occurs due to HPV infection, which is the only cancer of which the cause is clear. Since the cause is clear, it can be prevented. It takes more than ten years for precancerous lesions (cervical lesions) caused by HPV infection to infiltrate. This period gives us many opportunities to intervene and interrupt this cancerous process. Therefore early detection of precancerous lesions is needed. The most common screening method in the general population is cancer screening, i.e. TCT/CCT/LCT, etc. This method is simple, non-invasive and is the first part. If the results suggest abnormalities, such as low grade intraepithelial neoplasia, high grade neoplasia, etc. then further colposcopy is required, which is the second step. A biopsy should always be done during colposcopy to clarify the presence of precancerous lesions. If there are high-grade precancerous lesions such as severe atypical hyperplasia (CINIII) or cervical carcinoma in situ (CIS), further cervical conization is required, which is the third step to clarify whether there are more serious lesions such as invasive carcinoma. This concludes the diagnosis of precancerous lesions. For CINIII/CIS conization is also a treatment in itself, and if the excision is clean, the treatment ends at the same time, especially for patients who need to preserve their uterus for childbirth.