A multi-functional calendar structure includes a calendar made up of a set of upper and lower layers wherein the upper layer has week elements, day elements, and month elements respectively marked at the front face thereon, and a plurality of empty elements for recording important occasions or favorable/forbidden events in the month sequentially arranged at the bottom of the front face thereon. Each of the day and empty elements is provided with a set of top and bottom dotted tearing lines, a set of transversely U-shaped left and right cut areas disposed at both adjacent edges of the top/bottom dotted tearing lines thereof, an oblique cut opening defining the lower section of the left cut area thereof, and an adhesive portion properly coated at the reverse face thereon and limited within the left/right cut areas thereof. The lower layer is also provided with identical day and empty elements in corresponding positions relative to that of the upper layer thereof. Therefore, the day/empty elements with memo recorded thereon can be easily detached from the upper layer to serve as notes for easy carry outside, while identical copies of the memo can be left on the corresponding day/empty elements of the lower layer for further reference by other people. Besides, via the adhesive portions thereof, the note can be easily attached to an obvious position in cars or the offices as a reminder, efficiently providing a multi-functional calendar thereby.