A needle retractable type safe self destructing syringe which comprises a barrel body (1). A needle base body (3) is arranged within a barrel neck of an end part of the barrel body (1). The barrel neck (2) and the needle base body (3) form therebetween a flexible cushioning stopper mechanism. An asymmetric retracting locking piece having a flexibility feature is arranged at an end part of a syringe plunger (5). The flexibility feature implements engagement with and locking onto an outer sleeve type retracting locking component (5) in a cavity of a needle base. In a stress environment of an asymmetric force the needle base deflects to a side after being retracted into the barrel body (1) while an injection needle therefore swings in the direction of a nearly 45 degree angle to a side of the inner wall of the barrel body (1) and is locked by a neck part of the barrel body. This prevents an injection needle and the needle base from being pushed out of the barrel neck of the barrel body again effectively prevents secondary injury caused by the needle being pushed out and implements truly safe self destruction of the syringe. The asymmetric flexible retracting locking piece is a plastic barb body (12)； same is formed with the plunger in a single mold forming.
