The invention relates to the technical field of preparation of biological functional materials, in particular to a double-emission fluorescent molecularly imprinted polymer nanoparticle and its preparation method and application. In the present invention, carbon quantum dots are coated in silica nanospheres as the inner core of a ratiometric fluorescent probe, and then red cadmium telluride quantum dots are used as response signals, and acrylamide and 4-vinylphenylboronic acid are used as bifunctional single Using N,N-methylenebisacrylamide as a cross-linking agent and dopamine as a template molecule in the alcohol phase through the initiation of azobisisobutyronitrile to synthesize a dual-emission fluorescence with a specific recognition site for dopamine Molecularly imprinted polymer nanoparticles, and then prepared a fluorescent detection test paper with visualization effect by impregnation method, so as to realize the visual detection of DA, and the detection results of DA in human serum samples proved that the fluorescence detection paper prepared by this method The detection test paper can be used for semi-quantitative detection of DA in actual complex samples.