Safe self-destruction syringe with puncture proof protective sleeve

A syringe, comprising a needle cap (1), a needle (2), a needle seat (3), a protective sleeve (4), a coupling device (5), a locking member (6), a syringe body (7), a plunger shaft (8), and a plunger head (9), wherein said needle (2) is affixed to and extended from said needle seat (3), wherein said needle seat is detachably connected to said coupling device (5), which is provided at a top end portion of said protective sleeve (4), while said locking member (6) is received in another end portion of said protective sleeve (4), wherein said locking member is connected with a lower end surface (12) through conventional adhesive agent or welding technology by means of a welding wire (17), wherein said plunger head (9) is provided at a top end portion of said plunger shaft (8), which are movably received within said syringe body, wherein said syringe body, said plunger shaft, and said plunger head are all operatively received in said protective sleeve, wherein said syringe body (7) has a luer taper (10) for connecting with said coupling device through threading mechanism, wherein said coupling device has a circular cross section defining an inner cavity (15), and a plurality of coupling members (16) spacedly extended on said coupling device, wherein said coupling members (16) are arranged to couple with said luer taper (10) of said syringe body, wherein said syringe further comprises a resilient flanges (18) operatively connected with said locking device (6) which interlocks with said needle (2), said needle seat (3) and said coupling device (5) by operation of a sliding action of said flanges (18) in a backward direction.