Objective By using small interfering RNAs ( siRNAs) specific for spleen tyrosine kinase ( Syk) , to evaluate the role of Syk in maturation of bone marrow-derived dendritic cells. Methods The fragments of 21-23 bp siRNAs specific for mice Syk were chemo synthesized and transfected into the asthmatic murine bone marrow-derived dendritic cells ( BMDCs) by Lipofectamine 2000 transfection system for 48 hours. Then BMDCs were co-cultured with T cells from the normal mice spleen for 48 hours. The cytokines including IL-4, IL-13, IL-2 and INF-γin supernatant were detect by ELISA. The expression of Syk protein was measured by Western Blot to determine whether the Syk gene was silenced. Results The expression of Syk protein was obviously decreased in the siRNA-interference group. The secretions of IL-4 and IL-13 were significantly inhibited by siRNA interference ( P lt; 0. 05) , but the secretions of IL-2 and INF-γwere not interfered signficantly ( P gt;0. 05) . Conclusion Syk specific siRNA fragments can block the antigen presentation function of dendritic cells and block the activation and differentiation of T cells.