The invention relates to a safe syringe comprising a barrel, a needle seat and a plunger, wherein the needle seat has a hook rod, a linkage deformation portion and a barrel clamping portion； and the plunger has a rod body, and a hook insertion hole which can be sleeved with the hook rod of the needle seat and compress the linkage deformation portion for elastic deformation such that the barrel clamping portion of the needle seat is not clamped into the seat clamping slot of the barrel, and the hook insertion hole can hook the hook rod of the needle seat to move the needle seat. The safe syringe can allow stable positioning and quick pullback of the needle seat and effectively reduce liquid medicine residue.一種安全注射器，包含有一針筒，具有一筒身，一容室，一裝座孔，一卡座槽；一針座，具有一座身裝設於該針筒的裝座孔，一針孔，一勾桿，一連動變形部連接於該勾桿，及一卡筒部接於該連動變形部受其連動並可卡止於該針筒的卡座槽；一桿塞，具有一桿身，以及一插勾孔可套接該針座的勾桿並壓縮該連動變形部彈性變形使該針座的卡筒部不卡止於該針筒的卡座槽，該插勾孔可卡勾該針座的勾桿使移動該針座。
