The invention provides a cup grabbing mechanism which comprises a driving mechanism, a straight rod 17, a fixing substrate 1, a sliding base 10, a sliding part 11 and a cup grabbing claw 14. The sliding base 10 is fixed to the lower end face of the fixing substrate, the straight rod sequentially penetrates through the fixing substrate and a sliding groove, and the lower end of the straight rod is connected with the sliding part 11 embedded in the sliding groove. Two inclined guide holes 15 are correspondingly formed in the front side face and the rear side face of the sliding part respectively, and horizontal guide gaps in which inclined groove sliding pins move in the horizontal direction are formed in the sliding base. The top ends of two hook bodies forming the cup grabbing claw are connected with the two inclined groove sliding pins 12 respectively, and the sliding part moves vertically to drive the inclined groove sliding pins to horizontally move in horizontal sliding grooves so as to drive the cup grabbing claw to achieve opening and closing movements. The cup grabbing mechanism is simple in structure, small in occupied area, high in reliability, convenient to operate and capable of reducing maintenance difficulties to the largest extent.