An injection needle includes a needle hub and a needle tube. The needle hub is connected to a safety protective cover by an elastic flip mechanism. Two symmetrically-distributed needle hub hooks are provided on a side wall of the needle hub. Two symmetrically-distributed protective cover snaps are provided in a hollow inner cavity of the safety protective cover. The two protective cover snaps cooperates with the two needle hub hooks. Protective cover snap stoppers are provided on outer sides of the two protective cover snaps. The injection needle employs the two needle hub hooks disposed on the side wall of the needle hub and cooperate with the two protective cover snaps disposed in the inner cavity of the safety protective cover.