Objective To investigate the biological response of survivin siRNA in A549 human lung cancer cells and Hela S3 human cervical cancer cells as well as K562 human erythroleukemia cells,in order to screen the working sequences of survivin siRNA.Methods Three sequences of survivin-targeted siRNA were designed and synthetized,and human cancer lines of A549,Hela S3,K562 were transfected with Hiperfect liposome entrapped survivin siRNA,respectively.The expression of survivin mRNA was detected by means of real-time polymerase chain reaction (RT-PCR) with SYBR Green Ⅰ.Cell proliferation was detected by way of WST-8 cell count kit at 48 hours and 72 hours after transfection.Results The expression of survivin mRNA in all 3 cancer cells studied was significantly inhibited by all siRNA at 48 hours and 72 hours after transfection,gene expression inhibition ratio were 57.47％-88.53％ after transfection 48 hours and were 69.94％-95.03％ after transfection 72 hours.Cell proliferation was also significantly inhibited 48 hours and 72 hours after transfection,cell multiplication inhibition ratio were 27.88％-47.36％ after transfeotion 48 hours and were 42.59％-57.29％ after transfeciton 72 hours.Sequence 1 had the most inhibition efficacy on survivin gene expression and proli-feration in tumor cells.Inhibition rate of the three tumor cell gene expression of survivin at 48 hours are above 75％,72 h all over 90％,48 hours of cell proliferation inhibition rate are above 40％,72 hours of more than 50％.Conclusions The chemo-synthesized siRNAs can significantly down-regulate survivin mRNA expression in cancer cell studies.Survivin siRNA is capable of inhibiting the proliferation of tumor cell in vitro and it might be a new strategy for tumor-targeted therapy.Sequence 1 is the most efficacious working survivin siR-NA in the study.