Abstract: Objective : It is suggested that the chemokine receptor CXCR4 plays an important role in the invasionand metastasis of cervical cancer, but there are few published articles about down-regulating the CXCR4 ex-pression to prevent the metastasis of uterine cervix cancer. The aim of this study was to construct RNA inter-fering retrovirus vector of CXCR4 and to investigate the expression of CXCR4 receptor in human cervix carci-noma Caski cells interfered with retrovirally mediated RNA interference targeting CXCR4. Methods : We de-signed and constructed the sequence of CXCR4-siRNA and inserted the sequence into the plasmids of retrovi-ral vector which contained Green Flu Protein named pSOS. The plasmids were assembled and installed intoretrovirus by transfecting the plasmids into PT67 cells which were then cultured for at least 25 days. We useddepurated supernatant of culture fluid to transfect cervix carcinoma cells named Caski cells which had beendivided into the control group and groups at 24h, 48h, and 72h after transfection. The expression of CXCR4mRNA and CXCR4 protein were detected by Real-Time PCR and Western bolt respectively. Results : Theretrovirus vectors pSOS-CXCR4 were successfully constructed. Compared with that of the control group, theinhibition rates of CXCR4 mRNA at 24h, 48h and 72h were 29.9%, 56.8% and 62.8%, respectively. The inhibi-tion rates of CXCR4 protein at 24h, 48h and 72h were 43.6%, 49.6% and 62.9%, respectively. Conclusion :The pSOS-HUS-siRNA can significantly inhibit the expression of CXCR4 in human cervix carcinoma cells, in-dicating that the pSOS-HUS-siRNA could probably supply a new method of gene therapy to block the inva-sion and metastasis of uterine cervix cancer.