The invention discloses a compact pneumatic fixture, and belongs to the mechanical field. The fixture comprises a fixed bottom plate, a push cylinder fixed seat, a main push cylinder, a clamp retainer, a clamp clamping part, an auxiliary pressing cylinder, a workpiece location block, a main pressing cylinder, a front support block, a rear support block and a workpiece. Due to the mutual cooperation of the clamp clamping part, the front support block and the rear support block, the actual clamping range is expanded, and the actual machining requirements of most of parts can be met; the whole clamp realizes automatic clamping and automatic releasing under the action of the cylinders, so that the reliability of the clamp is improved, and in a working process, the efficiency of placing in theworkpiece and taking out the workpiece is increased; and the whole process is completely pneumatically controlled, so that missing clamping for the workpiece is avoided, and faults in the working process are reduced, and the clamp clamping part and the location block can be adjusted according to the specifications of the workpiece, so that the application range of the clamp is expanded.