Cervical precancerous lesions are a group of lesions closely related to cervical infiltrative carcinoma, which in cervical lesions refers to cervical intraepithelial neoplasia (CIN), usually referred to as CIN. This proliferation reflects the continuous process in the development of cervical cancer. According to the extent of atypical hyperplasia cells in the cervical epithelium, CIN is classified into I, II and III, which can also be called mild, moderate and severe, among which CIN III includes severe atypical hyperplasia and carcinoma in situ. Some patients have the following misunderstandings when seeking medical consultation: 1. Precancerous lesions are cancer, this understanding is wrong. Cancer is what we usually call malignant lesion, while precancerous lesion is a pre-cancerous process in the development of cancer, which can be interpreted as a lesion closely related to the occurrence of cancer, or more likely to develop into cancer compared with other lesions, and needs more attention. 2.Cervical carcinoma in situ is early infiltrating carcinoma. In situ carcinoma, the lesion cells occupy the whole layer of epithelium but do not break through the epithelial basal layer, which is essentially different from infiltrating carcinoma, and it does not metastasize, so it is not included in the statistics of cervical cancer in medicine.