Cancer is one of the most serious health hazards, and as the saying goes, cancer is a major concern. Interrupting cancer before it appears is a growing concern. The occurrence of cancer is usually a pre-cancerous process that lasts for many years, but not a leap into cancer. In emphasizing primary prevention to treat the disease, the most effective method is early detection, early diagnosis and early treatment of precancerous lesions, i.e. secondary prevention. Pre-cancerous lesions refer to certain benign lesions that have the potential to become cancerous and may turn into cancer if left untreated for a long time. In other words, pre-cancerous lesions have the potential to turn into cancer, but not all pre-cancerous lesions eventually turn into cancer, and may return to normal or subside with appropriate treatment. Pre-cancerous lesions are divided into two categories: precancerous state and precancerous lesions. Precancerous state, also known as precancerous disease, refers to clinical conditions and diseases with significantly increased risk of cancer, such as chronic cervicitis. Precancerous lesions refer to tissue producing pathological changes, heterogeneous hyperplasia or atypical hyperplasia, such as cervical intraepithelial neoplasia.