The invention belongs to the technical field of supramolecular subject fluorescence detection, and a cyanostyrene supramolecular gel film is utilized for serving as a fluorescence probe which rapidly detects carbon dioxide in air. The gel film responding to carbon dioxide is an isophthalamide derivative taking a cyanostyrene compound as a basis. The supramolecular gel film fluorescence probe is prepared through a drop casting method, the preparation method is simple and easy to operate, and the preparation time is short. The prepared supramolecular gel film is short in responding time to carbon dioxide, and rapid detection on carbon dioxide in the air can be achieved. The sensitivity of the prepared supramolecular gel film to carbon dioxide detection is high, and the detection limit can reach 6 ppm.