Abstract: Objective: To explore the expression of p63 and Ki-67 protein in cervical intraepithelial neoplasia (CIN) and its significance. Methods: One hundred and twenty-six biopsy samples of the cervix were selected,and the expression of p63,Ki-67 protein and human papillomavirus(HPV) was detected by immunohistochemical technique. Among the samples,12 were normal controls,40 CIN1,31 CIN2,33 CIN3 and 10 invasive carcinomas. The invasive carcinomas were probed by low risk(LR)-HPV DNA and high risk human papilloma virus(HR)-HPV DNA using in situ hybridization(ISH) method. Results: The expression of p63 in the control group was negative,but that in the thickening cervical squamous epithelium might present positive cells. In the CIN1,CIN2,CIN3 and invasive carcinoma groups,the positive rates of p63 were 80.0%,96.8%,100.0% and 10/10; the positive rates of Ki-67 protein were 0.0%, 27.5%,64.5%,54.5% and 8/10; the positive rates of HPV were 33.3%, 17.5%,51.6%,39.4% and 3/10,respectively. In the invasive carcinomas,the positive rates of LR-HPV DNA and HR-HPV DNA were 5/10 and 8/10,respectively. The expression of p63 in CIN increased obviously with the upgrade of the histopathological degree,and was related with HPV infection(P < 0.05). Conclusions: The application of p63 combined with Ki-67 protein is of help to the screening,early diagnosis and treatment of cervical precancerous lesions.