A pneumatic retractable auto-disable syringe, comprising a syringe barrel (4), a hollow cylindrical plunger (3), a needle hub (5), a sealing ring (6), a piston (8) and a seal connector (7), wherein: the seal connector (7) and the needle hub (5) are provided with a compatible connection mechanism disposed thereon the inner wall of the syringe barrel (4) at the front end thereof and the outer wall of the needle hub (5) at the front end thereof are pneumatically sealed the plunger (3) is provided with a position limiting device (31) disposed on the inner wall thereof the plunger (3) is provided with an air vent (33) disposed at the bottom end thereof. The present invention is structurally simple, easy and inexpensive to manufacture, and easily assembled. The auto-disablement thereof is divided into two steps: first, the seal connector (7) is inserted into a hole in the needle hub (5) by means of manual force, and the seal connector (7) becomes loose once the injection fluid is completely injected second, as the sealing ring (6) continues to be pushed forward, air pressure is generated and the seal connector (7) is then ejected into the plunger (3) by the energy released from the compressed air. The lower precision requirements of the product allow for simpler and more reliable auto-disablement.
