siRNAs target sites selection of ezrin and the influence of RNA interference on ezrin expression and biological characters of osteosarcoma cells. Ezrin, one of the ezrin/radixin/moesin (ERM) protein family which act as membrane organizers and linkers between plasma membrane and cytoskeleton, has attracted much attention as a crucial factor for tumor metastasis. Overexpression of ezrin has been correlated with the metastatic potential of several cancers especially for osteosarcoma. Short interfering RNA (siRNA) downregulate gene expression through an enzyme-mediated process named RNA interference (RNAi). RNAi has rapidly come to be recognized as a powerful tool for the study of gene function and a potential target therapy. In the present study, the human osteosarcoma cell line MG63 was cultured. Three siRNAs targeting ezrin mRNA were designed by the multiple computational methods and then were sythesized. These siRNAs were transfected into osteosarcoma cells. Then the expression of ezrin mRNA and protein in osteosarcoma cells was detected. The cellular proliferation and apoptosis was evaluated. C726–U730, C1653–A1661 and G1749–A1771 were selected to be the suitable target sites through the multiple computational methods because of their ideal secondary structures and hybridization thermodynamics. siRNAs against G1749–A1771 downregulated the expression level of ezrin mRNA and protein, inhibit the cellular proliferation and promoted the cellular apoptosis effectively. There is a significant correlation between the multiple computational methods and the efficacy of the corresponding siRNAs. siRNAs targeting ezrin may have therapeutic potential as inhibitors of osteosarcoma metastasis.