Infectious bursal disease virus (IBDV), the causative agent of a highly contagious disease in chickens, carries a small nonstructural protein (NS). In this study, vvIBDV Gx-VP5 genes were cloned into plasmid pET30a( + ) and expressed in E. coli with IPTG inducing. BALB/c mice were immunized with the purified recombinant fusion protein. SP2/0 myeloma cells and spleen cells of BALB/c mice were fused by PEG(MW1500), three hybridoma cell lines were examined by indirect ELISA and clone for three times by limited dilution, and were named as 4B4, 6D12, 3E8. The subtype of the monoclonal antibodies were IgG1 with a subtype identified ELISA kit, and light chains were kappa. The ascites titers of monoclonal antibodies were 5 x 10(4), 3.5 x 10(4), 3 x 10(4) by indirect ELISA, respectively. Indirect ELISA and Western blot results showed that the monoclonal antibodies only acted with VP5 protein, IF analysis indicated that three monoclonal antibodies acted with IBDV Gt. There were specific fluorescence in detected Vero E6 cells which transient expressed VP5 protein by IFA. Therefore, monoclonal antibodies specific to IBDV VP5 proteins are specific method for detected VP5 proteins, and base on establish stabilize expressed VP5 protein Vero cell lines to research IBDV VP5 protein function.