A safety syringe assembly and a replaceable base unit are disclosed. The replaceable base unit of the present invention includes a base portion, a needle cover and a disengagement actuator. The base portion is configured to detachably connect with a syringe holder and has a through-hole structure, which is used to connect with an external needle. The needle covers proximal end is connected with the base portion to allow the needle cover to move with respect to the base portion, enabling it to contain and cover the syringe needle. The disengagement actuator is configured on the base portion and disengages the base portion from the syringe holder in pressing mode.本發明係一種安全持針器組及其可置換式底座。前述之可置換式底座包含一座體、一防針扎護具以及一按壓部。座體係用以活動式連接外部一持針器,其座體更設有一貫孔,該貫孔係用於連接外部針具之連接部。防針扎護具之一端係與座體連接,其防針扎護具可相對於座體活動,並於蓋合模態下覆蓋針具之針頭。按壓部係設於座體之一部,並於按壓模態下以分離座體以及持針器。1‧‧‧可置換式底座11‧‧‧座體12‧‧‧防針扎護具13‧‧‧按壓部14‧‧‧貫孔15‧‧‧卡接部
