The invention discloses a mold and method for producing a prefabricated post-grouting special-shaped root pile. The mold comprises a bottom support, a first half-barrel-shaped pile side mold plate, a second half-barrel-shaped pile side mold plate and a steel strip, wherein the first half-barrel-shaped pile side mold plate and the second half-barrel-shaped pile side mold plate are fixed to the bottom support and are in detachably butt joint with each other, so that a barrel is formed. The inner wall of the first half-barrel-shaped pile side mold plate is provided with first arc plates, and the inner wall of the second half-barrel-shaped pile side mold plate is provided with second arc plates, wherein the first arc plates and the second arc plates are arranged in the circumferential direction in an equally-spaced manner. The first arc plates and the second arc plates are symmetrically arranged. The outer edge of the top of the first half-barrel-shaped pile side mold plate is provided with a first semi-ring-shaped reinforcing rib piece, and the outer edge of the top of the second half-barrel-shaped pile side mold plate is provided with a second semi-ring-shaped reinforcing rib piece, wherein the first semi-ring-shaped reinforcing rib piece and the second semi-ring-shaped reinforcing rib piece are coplanar with the top end face of the barrel. The bottom support is provided with a central fixing hole, wherein the central fixing hole is used for fixing a central steel tube in the prefabricated root pile arranged in the center of the barrel. The two ends of the steel strip are fixed to the first semi-ring-shaped reinforcing rib piece and the second semi-ring-shaped reinforcing rib piece correspondingly, and a round hole is formed in the center of the steel strip and used for fixing the top end of the central steel tube. The mold is convenient to demount and mount and capable of being used cyclically; and the central steel tube is fixed, so that the bearing capacity of the pile end is guaranteed, and pile production efficiency is improved.