The utility model relates to a quick ball grinder. A rotation shaft is arranged on a belt pulley which is driven by an electrical machine of the quick ball grinder in an eccentric mode. A grinding cup is fixed tightly on the rotation shaft, and the grinding cup can make circumferential motion around the center line of the belt wheel. Both ends of a connecting rod are respectively hinged on swing rods on the rotation shaft and a frame, and the grinding cup also judders when rotating. The rotation speed of the grinding cup can be enhanced greatly. The materials which are ground can not rotate along with the grinding cup because of the centrifugal force, and the work efficiency is enhanced.