Abstract： Objective Through the detection of kallikrein 7 (KLK7) expression in different grades of cervical lesion tissues,to explore the role of KLK7 in the development of cervical precancerous lesion,screening of high-risk individuals,individual guide the clinical treatment for CIN. Methods Paraffin sections of 120 cases were collected,the expression of KLK7 by immunohistochemical method in the CIN tissue,and the tissue of chronic cervicitis,cervical squamous cell carcinoma as control,to analyze the expression level of KLK7 in tissues of cervical precancerous lesions,the correlation of their expression level and CIN at different levels of analysis. Results This study showed that KLK7 widely exists in the CIN cytoplasm and nucleus in chronic cervicitis,there was significant difference between the group and the CIN group and cervical carcinoma group,there was significant difference in CIN classification.The positive rate of KLK7 in high level CIN and cervical cancer were significantly higher than those of low grade CIN and chronic cervicitis.Chronic cervicitis tissue KLK7 expression,but positive results in low expression, the positive rate was 52.5%,but weakly positive expression of the total positive rate of 92%.And with the increase of CIN level, the number of positive cells increased significantly,staining gradually deepened,the positive rate of CIN1 increased from 77.5% to 97.5% of CIN3,the strong positive rate to 72.5% of CIN3 rise from 5% of CIN1.The positive rate of cervical cancer in moderate amounts to 87.5%,while the CIN1 and CIN2 strong positive rate was only 21.2%. (P <0.05). Conclusion The expression of KLK7 in the development of CIN,the continuous process of gradually increased,may be involved in the tumorigenesis of cervical precancerous lesion,the high expression of KLK7 may be associated with cervical cancer.Detection of KLK7 may predict the prognosis of cervical precancerous lesions.