The invention provides an effective and environmentally friendly antibody protective agent and the methods of using it in immunological detection. The antibody protective agent helps antibody to maintain relatively high immunological activity at room temperature. Working electrodes coated with antibodies and the antibody protective agent are installed in immunological detection devices to enhance stability and accuracy of immunological detection. The antibody protective agent is effectively used in the detection of a variety of toxins, for example, aflatoxin, staphylococcal enterotoxin, algae toxin, and vomitoxin.