The invention belongs to the technical field of chemiluminescence biology, and particularly relates to a fluorescence resonance energy transfer technology which is applied to detection of antigen-antibody affinity interaction. The invention provides an FRET (Fluorescence Resonance Energy Transfer) detection technology which comprises the following steps: selecting fluorescein isothiocyanate (FITC) and Rhodamine B as fluorescent markers, pretreating the Rhodamine B and a coupling agent EDC/NHS to activate carboxyl groups, carrying out labeling reaction on fluorescein groups and antigens and antibodies, screening and purifying labeled samples through Sephadex G-25, reacting the labeled antigens and antibodies in an elisa plate, and detecting the fluorescence in the elisa plate. FRET technology is utilized to measure fluorescence intensity, and interaction is detected. The detection technology provided by the invention aims to establish a platform by utilizing a fluorescence labeling technology, is used for screening and detecting the interaction of the antigen and the antibody, is a convenient technology which does not need repeated incubation and washing circulation, can be directly used for reaction detection in a solution, and can be applied to the aspects of antibody preparation, immunotherapy research, protein function detection and the like.