The invention discloses a safety self-destructive syringe, and the difference thereof from the prior art lies in: the syringe, an extension shrapnel on the neck of the inner syringe of the syringe, a core rod, a piston sleeved on the front end of the core rod, a piston fixing seat, a replaceable needle seat which is matched with the syringe body and can be pulled back, a seal ring, a needle seat and a needle. The replaceable needle seat is fixed and matched with the extension shrapnel on the neck of the inner syringe of the syringe body at the rear part. After injection is over, the piston fixing seat on the front end of the core rod pushes the extension shrapnel on the neck of the syringe outwards; and after the injection, a pull-back connection column on the front end of the core rod smoothly pulls the needle seat back into the syringe body, and a ring on the syringe body which prevents the core rod from being pushed back and being pulled out is used for locking the core rod, so that the core rod cannot move forwards or be pulled back. The safety self-destructive syringe breaks through the design philosophy of a traditional syringe, and has the advantages of reasonable structural design, high safety, low manufacturing process difficulty, few procedures, cost saving, easy production and easy popularization.