Using hybridoma techniques, six hybridoma celllines: 4D6, 4D4, 4F10, 3H6, 3H8 and 4E9 secreting monoclonal antibodies to Shanghai Isolate of Barley yellow mosaic virus (BaYMV) were prepared by fusion between myeloma cells NS-1 and spleen cells of BALB/C mouse immunized with BaYMV. The subclasses of monoclonal antibodies obtained belong to IgG2a. The cross-reaction test with different viruses (SMV, TMV and three isolates of TuMV) showed that six monoclonal antibodies were specific to BaYMV. The titers of six monoclonal antibodies to BaYMV in their cell cultured supernatauts were 1:1-5 x 10(4), and that of 4F10 in ascitic fluid was 1:6.4 x 10(5) by using indirected ELISA test respectively.