The invention provides a data output/input method with application of an image index structure. The data output/input method comprises the steps of: forming at least one image index structure corresponding an index datum on an object surface, wherein the image index structure comprises a content data part and a header part, the content data part comprises a plurality of micro image units, a region occupied by the content data part is divided into a plurality of state regions, each state region is provided with one micro image unit, the micro image unit is optionally located in one of a plurality of virtual regions formed by uniformly dividing the state region, the header part comprises a plurality of micro image units which are arrayed in a preset manner so as to provide header information for recognizing an image index; and optically reading the object surface so as to obtain an amplified image containing the image index structure to further capture the index data corresponding to the image index structure.