To prepare monoclonal antibodies (mAb) against Brucella ribosomal protein L7/L12 for establishing foundation of investigation methods and immuno-agents, the mAbs against protein L7/L12 were made by routine procedures: immunizing mice, fusing cell and cloning. Then specificity, epitopes recognization and relative affinities of mAbs were identified by Western blot and ELISA.Four strains mAbs were obtained,named of 1B1, 2A2, 2H9 and 2H10 respectively. The mAbs could recognize similar epitopes but still existed some differences. The results suggested that the four antibodies are stably and could bind to the L7/L12 protein specifically.