The invention provides a colloidal gold cassette for rapid detection of melamine, the colloidal gold cassette has rapid detection, convenient carry and simple operation, the invention also provides a preparation method of the cassette, the preparation process thereof is simple, and the cost is low. The colloidal gold cassette comprises a test strip, the test strip is packaged in a shell body of the cassette, a sample adding hole and an observation hole are arranged on the shell body of the cassette, the test strip comprises a bottom plate, the colloidal gold cassette is characterized in that water absorbent paper, a nitrocellulose membrane, a gold-labeled pad and a sample pad are sequentially arranged on the bottom plate of the test strip, the water absorbent paper and the gold-labeled pad are respectively arranged at the two ends of the nitrocellulose membrane, small sections of the water absorbent paper and the gold-labeled pad are respectively overlapped on the nitrocellulose membrane at the junctions at the two ends of the nitrocellulose membrane, the sample pad is arranged at the other end of the gold-labeled pad, a small section of the sample pad is overlapped on the gold-labeled pad; a gold-labeled anti-melamine monoclonal antibody is sprayed on the gold-labeled pad; a detection line with the material of a melamine-ovalbumin coupled conjugate and a quality control line with the material of goat anti-mouse IgG are sequentially sprayed on the nitrocellulose membrane.