Abstract: Objective To investigate the effect and its mechanism of stem cell related transcription factor Sox2 on the proliferation of cervical squamous carcinoma cell line SiHa. Methods Plasmid pIRES-EGFP-Sox2 or empty plasmid (pIRES-EGFP-empty) was stably transfected into SiHa cells. The expression of Sox2 was detected by both RT-PCT and Western blot. The effects of Sox2 on cellular proliferation and cell cycle were studied by MTT assay and flow cytometry (FCM) respectively. The expression of cell cycle related protein CyclinD1 was detected by Western blot. Results Compared to SiHa-EGFP cells, the expression of Sox2 was obviously up-regulated in SiHa-Sox2 cells(PSox2 cells grew faster than the control cells．The over-expression of Sox2 increased the proportion of transfected cells in phase S. The increased expression of CyclinD1 was further detected after the successful expression of Sox2(P<0.05). Conclusion Sox2 could enhance the proliferation of cervical squamous cancer cells in the manner of up-regulating CyclinD1 expression.