An air spring torsion testing device for a railway vehicle comprises a common testing machine, on which a fatigue test tool set comprising an air chamber connecting rack, a sealing rubber bearing pad, a mirror surface corrosion resistant plate, a Teflon plate, a lower elevation support and a torsion device is arranged. The fatigue test tool set comprises a vertical loading part and a horizontal loading part. The vertical loading part comprises the air chamber connecting rack, the sealing rubber bearing pad, the mirror surface corrosion resistant plate, the Teflon plate and the lower elevation support, wherein the lower elevation support is arranged in the center position of the testing machine, and the upper surface of the lower elevation support is integrally connected with the Teflon plate through a fastener to prevent the air spring from causing slippage of the Teflon plate during torsion process. The horizontal loading part adopts the torsion device which comprises a torsion arm, a torsion connecting rod, a torsion pin, a horizontal guide device, an oil cylinder elevation support and an actuating cylinder, wherein the torsion arm is connected with the torsion connecting rod through the torsion pin.