The present invention provides a product label with a colorimetric sensor array and a code, and the system and the method of the present invention are mainly that the product label is attached to a fresh food, so that at least one sensing material of the colorimetric sensor array undergoes a chemical reaction with at least one metabolic molecule of the fresh food to change from an initial color to an indicating color. The present invention, by obtaining an image comprising an appearance, the code and the indicating color of the fresh food through an image acquisition device, also provides an instant information associated with the fresh food by a processing device according to a comparison result of the image and a database.