The invention discloses a kit for detecting 3-methyl-quinoxaline-2-carboxylic acid. The enzyme linked immunosorbent assay (ELISA) kit for detecting 3-methyl-quinoxaline-2-carboxylic acid comprises a monoclonal antibody which has an anti-preservation number of CGMCC No.5778 and is excreted by an olaquindox metabolite monoclonal antibody hybrid tumor 5A2. The kit comprises the monoclonal antibody, and a conjugate of a compound and a barrier protein, which is shown as a formula (I). The kit has the advantages of high sensitivity, high accuracy, high precision, low cost, simplicity for operation, short detection time, suitability for use by various units, simplicity for storage and long shelf life, can be used for quickly detecting a large number of samples at the same time, and can realize on-site high-flux quick detection. The ELISA kit is suitable for determining the residual quantity of olaquindox metabolites in feeds, animal tissues or excrements. The antibody, the kit and a detection method can play a major role in detection of the olaquindox metabolites.