The antigenic conjugate of norfloxacin and bovine serum albumin ( BSA) was prepared by carbodiimide method. 16. 1 norfloxacin residues were linked to a molecule of the BSA in the conjugate by method of UV spectrum. The conjugates of norfloxacin-ovalbumin (OA) used for coating antigen were synthesized by carbodiimide method and mixed anhydride method, respectively. The number of norfloxacin residues per molecule of the conjugates was 5 .8 and 1.9.