The present invention discloses a disposable self-destructive syringe, which belongs to syringes for medical treatment, comprises a needle (1), a tube (2), a injecting piston-rod (3), ratchet grooves (4), a restrictive step (5), an installation opening (6), an anti-return member (7), anti-return prods (8), ratchets (9), a sealing plug (10) and reciprocal motion region (11). The needle is conglutinated on the tube, the injecting piston-rod is arranged in the tube, the anti-return member is arranged in the gap of the injecting piston-rod and in the rear end of the tube, and the sealing plug is arranged in the tube and mounted on the front end of the injecting piston-rod. The syringe is convenient to discharge the inhaled air as sucking medical liquid, begins to be self-destructive after sucking for predetermined amount and can not suck medical liquid again during and after injecting. Further more, the ratchet grooves arranged on the injecting piston-rod can be one or more, which the fewer the number of ratchet grooves, the larger the interval of discharging inhaled air will become. The disposable self-destructive syringe according to the invention of which dose is precise is convenient to operate and will be self-destructive once used.
