Abstract: Objective To investigate the role of chemokine 12（CXCL12） in regulating the radiosensitivity of cervical cancer. Methods CXCL12 siRNA was transfected into cervical cancer HeLa cells by cationic liposome（siRNA transfection group）. The blank control group and the negative control group were set up. The HeLa cells in each group were irradiated with different doses （4， 8 Gy）. Cell viability was determined by CCK-8 assay. The apoptosis rate and expression of CD44 was detected by flow cytometry. ELISA method and realtime quantitative PCR （QPCR） were used to detect the change of CXCL12 expression. Results After 4 and 8 Gy irradiation, the survival rates of siRNA transfection group were 62.0％ and 44.0％， which were lower than 79.0% and 59.0% of the negative control group， and the difference was statistically significant （P＜0.05）. After 4 and 8 Gy irradiation, the apoptosis rates of siRNA transfection group were 28.0％ and 51.0％， which were higher than 21.0％ and 39.0％ of the negative contol group， and the difference was statistically significant （P＜0.05）. After 4 and 8 Gy irradiation, the expression of CD44 protein in the siRNA transfection group was 1.33 ±0.02 and 1.40±0.01， which was lower than 1.55 ±0.02 and 1.85 ±0.02 in the negative control group，and the difference was statistically significant （P＜0.05）. Conclusion Silencing CXCL12 can increase the radiosensitivity of cervical cancer cells by inhibiting cell proliferation and promoting apoptosis， and CXCL12 may be a new sensitizing target for cervical cancer radiotherapy.