The invention belongs to the field of ring rolling tool equipment and discloses a special tool locking device for an production process of asymmetrical irregular section ring rolling. The special tool locking device is characterized by comprising two groups of locking mechanisms, wherein each group of locking mechanism comprises two corresponding locking rings for locking an irregular main roller. One side between the two locking rings of each group of locking mechanism is connected with a locking screw through a lock catch, and the other side between the two locking rings of each group of locking mechanism is connected with the lock catch through a bolt group. The device can fix the irregular main roller during the ring rolling, prevent the end face play of the irregular main roller and ensure uniformity and stability during rotating and flattening, thus overcoming the defects of the end face play during the ring rolling and the like; and moreover, the improved equipment is suitable for the production process of asymmetrical irregular section ring rolling, and the mass production of asymmetrical irregular section ring rolling pieces can be realized.