A disposable sterile retracting blood taking needle consists of an end cover, a protective sleeve, a needle guard, a needle, a needle hub, a core rod. An outer sleeve, a piston, a sheath and a blood taking needle. The piston is arranged in a clamping groove of the core rod the outer sleeve is sleeved on the core rod and the piston the piston and the outer sleeve are in interference fit inner holes of the needle, the needle hub, the core rod and the blood taking needle are communicated the core rod and the outer sleeve are made of transparent materials blood backflow is judged by blood flowing in a passage in the core rod and after blood taking is completed, a medical worker presses a blood taking position of the blood taking needle with one hand, presses the outer sleeve with a finger of the other hand and pulls the needle guard to move back with other fingers of the other hand, so that a snap ring of the core rod enters a slot of the outer sleeve and is locked, and the blood taking needle is hidden in a cylinder of the outer sleeve, and thus the aim of safety is fulfilled.
