Needle-safety syringe is unloaded in a kind of propulsion, comprising: a syringe has a push rod being reciprocally moveable in the syringe； The front inner wall of the syringe connects a syringe needle by one engagement seat of connected structure assembling, the engagement cover for seat. The connected structure is agreed with the cone cell outer wall of a cone cell inner wall and the engagement seat, the connected structure is constituted position-limiting action with the limited ring groove of the position limiting convex ring of a protrusion what syringe inner wall and the engagement seat, the connected structure is chimeric wherein for the chimeric ring of the engagement seat with an embeded slot, accordingly positions the engagement seat in the what connected structure. When the push rod anterior displacement to the chimeric ring for contacting the engagement seat； the connected structure and syringe can be pushed away forward together with syringe needle thereon for the engagement seat together by applying a thrust again； the needle body of Hou will be used to separate with syringe to reach, is pricked with protecting medical staff that the needle body for being used Hou is avoided to stab.一種推進卸針式安全注射器，包括：一針筒，該針筒中具有一可往復移動的推桿；該針筒的前端內壁通過一接合結構組裝一接合座，該接合座套接一針頭。該接合結構以一錐狀內壁與該接合座之錐狀外壁契合，該接合結構以一凸出於該針筒內壁之限位凸環與該接合座之限位環槽構成限位作用，該接合結構以一嵌合槽供該接合座之嵌合環嵌合其中，據此將該接合座定位於該接合結構中。該推桿向前位移至接觸該接合座之嵌合環時，再施一推力可將該接合座連同其上的針頭一併向前推離該接合結構及針筒，從而達到將使用後的針體與針筒分離，以保護醫護人員避免被使用後之針體戳扎。
