Abstract： Exfoliative cytology is a simple and non-invasive examination method that is easily accepted by the patient. A number of new techniques are used to further increase the accuracy of sample collecting. It is widely used in the detection of cervical, oral cavity and various coelom exfoliated cells. This article reviews the development of exfoliative cytology in oral cancer diagnosis. It is realized that the qualitative and quantitative analysis of cancer and precancerous lesions, through DNA quantitative analysis to calculate DNA index (DI value), multiple parameter analysis and statistical modeling calculation to evaluate oral cancer risk index (OCRI) of the patient has great significance in cancer screening, early diagnosis and prognosis review, especially in the field of oral cancer.