The utility model discloses a telescopic geological hammer which comprises a grip, a containing groove is formed in the side wall of the grip, a hammer rod is connected in the containing groove in a sliding mode, a supporting device is arranged in the containing groove, one end of the hammer rod extends out of the containing groove and is fixedly connected with a hammer head, four threaded holes are formed in the side wall of the hammer rod, and the hammer rod is connected with the supporting device in a sliding mode. Four threaded holes are formed in the hammer rod, the four threaded holes are symmetrically formed in the two ends of the hammer rod, two through holes are formed in the top of the grip, threaded rods are slidably connected into the two through holes, and the tops of the two threaded rods extend out of the corresponding through holes and are fixedly connected with rotating blocks. According to the portable geological hammer, under the mutual cooperation of the hanging belt, the grip, the scale marks, the hammer rod and other components, the hammer rod can be stretched out and drawn back, so that the length of the hammer rod is adjusted, the geological hammer is convenient to carry, the grip can be reinforced, the phenomenon that the grip is deformed after being used for a long time is prevented, the length of an object can be measured, operation is easy, and the applicability is wide.