The invention relates to a rotor structure for an impact crusher, belonging to the technical field of mining machinery. The rotor structure for an impact crusher comprises a rotor main shaft and hammer disks which are arranged on the rotor main shaft at intervals and provided with flat hammer seats. The rotor structure for an impact crusher is characterized in that the flat hammer seats are directly formed on the hammer disks, a flat hammer seat reinforcement block is arranged between two adjacent hammer disks and corresponds to the position of the flat hammer seat, and two sides of each flat hammer seat reinforcement block are welded fixedly to the flat hammer seat of two adjacent hammer disks. The flat hammer disks are not damaged by the big acting force of the flat hammers under the working state of the impact crusher due to the arrangement of the flat hammer seats which are directly formed on the hammer disks as well as the flat hammer seat reinforcement blocks which are between two adjacent hammer disks and correspond to the position of the flat hammer seat, the persistent working efficiency of the impact crusher is guaranteed, the maintenance cost is remarkably reduced and the waste of resources is avoided.