A portable astronomical telescope includes the cylinder body, on which three telescopic legs are hinged through a joint to form a tripod stand. The bottom of aforementioned cylinder body is fixed by means of connection element and mounted with part box. On the bottom end of this part box, a bottom cover is insert-mounted. On the upper end of the part box, limit connection elements of the connected telescopic leg are hinged. Within the aforementioned cylinder body, a guide bush is fixed and installed, inside of which telescope base is mounted. On the side of this telescope base, a guide pin is established. On the side of the guide sleeve, an L-shaped feed-through slot is established to accommodate the guide sleeve. On the tail end of the above feed-through slot, one guide pin residence slot is connected. The aforementioned telescope base is activated by the lug and mounted with bellows. This product can be used without need for separate assembly, and eliminates the need for a separate package. With small volume and light-weight features, it can hide the bellows within the cylinder body, in order to provide protection, which facilitates the product carrying and movement, particularly suitable for astronomy enthusiasts at the time of outdoor observation activities.