In this study, we investigated the distribution of the common Pro844Leu and Thr942Ile genotypes in Chinese women, and assessed the association of these polymorphisms or linkage disequilibrium with the risk of cervical squamous cell carcinoma (CSCC), CIN III and their interaction with HR-HPV infection, sexual and reproductive risk factors, and analyzed the MLH3 gene mRNA expression level and the effect on protein function. The gene discussed is MLH3; the disease is cervical squamous cell carcinoma.