The invention discloses a fixture for a milling machine, which comprises a fixed frame, a stable seat, a long hole, a clamping plate, a screw hole, a variable concave groove, a chute and a set screw. The upper end of the fixed frame is provided with a stable seat. The stable seat is provided with a chute, and the chute is provided with symmetrically arranged clamping plates, and the clamping plate is provided with screw holes, and the two clamping plates can slide in the chute, The two clamping plates and the chute form a variable concave groove, the side of the chute is provided with a set screw, and the set screw is used to fix the position of the clamping plate in the chute , The two sides of the fixing frame are provided with long holes. The invention has the advantages of simple structure, convenient use, wide clamping range and good fastening effect.