After a comparison of anti-AFM1-BSA antibody responses between rat and mouse, the spleen cells of rat with stronger responses were chosen as parent cells for fusing with mouse myeloma cells P3X63-Ag8.653. Through HAT medium selection, RIA screening and cloning, five well growing rat-mouse hybridoma clones were obtained that could secret anti-AFM1 antibodies stably. The results from ELISA and competitive binding RIA further proved that the 5 McAbs are direct against AFM1, with significant cross reaction to its derivative, AFB1. The average affinity constant of the 5 McAbs is 10(9)-10(11) l/M. It signifies that these monoclonals have potential application value for the construction of AF detection kit.