The invention discloses a jig for a motor rotor production line. The jig comprises a jig seat body, a first support seat and a second support seat, wherein the first support seat and the second support seat are arranged on the jig seat body; a slide chute is formed in the jig seat body; a slide bar is arranged at the upper part of the slide chute; the two support seats are simultaneously in sliding fit with the slide chute and the slide bar; and first clamps for camping the slide bar are arranged on the two support seats. Through the technical scheme, in the production process of motor rotors, the jig can adjust the distance between the first support seat and the second support seat for adaption even if rotating shafts of the rotors are different in length, so that saving of the production cost is facilitated; and the production technology of the motor rotors is simplified.