The utility model provides a special long muzzle for peritectic steel, and relates to mechanical attached parts. The special long muzzle comprises a flow control opening, an inner pipe body, a funnel opening and an inner runner, wherein the flow control opening is formed in the funnel opening; the funnel opening is connected with the inner pipe body; a protection region A is arranged on the inner pipe body; the inner runner is formed in the inner pipe body; an outer pipe body sleeves the inner pipe body; a clamping piece is arranged at the top of the outer pipe body; a protection region B is arranged in the middle of the outer pipe body; a base is arranged at the bottom of the outer pipe body; a runner outlet is formed in the base. The outer pipe body is arranged outside the long muzzle, so that the inner pipe body can be further protected, and the quality of the peritectic steel can be improved; the protection regions are arranged on the outer pipe body and the inner pipe body in order to enhance the abrasion resistance, and the service life of the long muzzle is longer; resources can be effectively saved.