Abstract： Objective To study the expression of Ki67 in cervical intraepithelial neoplasia and their clinical significance. Methods Immunihistochemistry S-P method was used to detect the expression of Ki67 in normal cervical epithelium, CIN Ⅰ , CIN Ⅱ and CIN Ⅲ. Results The positive expression of Ki67 was 10%, 36.4% ,84. 6%and 92. 3% in 47 cases ( normal cervical epitheliumlo,CIN Ⅰ11 ,CIN Ⅱ 13and CIN Ⅲ 13) ,it was significantly different between every sets(P < 0. 05). Conclusion Ki67 could reflect the propagate an activity of the cervical cells in their chang process, which could be used as markers for early diagnosis of cervix ceancer. It could be helpful for inckeasing the ratio of earlier diagnosis in cervical cancer.