The present application discloses a safety injection needle, comprising a needle base provided on the end potion thereof with a needle tube, characterized in that the needle base being provided at one side with a safety sheath, an elastic telescopic plate being provided at the junction between the safety sheath and the needle base, the safety sheath rotatable about the elastic telescopic plate and having a hollow cavity which is provided therein in sequence with a sheath safety hook and a needle tube safety hook, the needle base being provided with a needle base safety hook cooperating with the sheath safety hook. The safety protection mechanism is integral with the needle base and the multiple-segment engagement mechanism. Compared to the conventional product, the present invention possesses prominent substantive feature and notable development.