The utility model discloses a horizontal positioning device for a rotary electrode extruder. The horizontal positioning device is characterized by being provided with a fixing supporting mechanism and a horizontal locking mechanism. The fixing supporting mechanism comprises wedge blocks arranged at the two ends of the upper surface of a base, a V-shaped block to which a base plate is fastened is arranged between the wedge blocks, a bolt combination and a jackscrew are arranged at the positions, opposite to the side edge of the base, of the lower portions of the side edges of the wedge blocks. The horizontal locking mechanism comprises fixed wedges and sliding plates, wherein the fixed wedges and the sliding plates are fixed to the rear portion of the base in pairs through bolts. A dovetail block is embedded between the inner side faces of the two fixed wedges and a hydraulic cylinder is installed in the front of the base through a hydraulic cylinder support. Movable wedges are fastened to I-shaped blocks through bolts. A T-shaped groove is formed in one side of a cross beam. One sides of the I-shaped blocks are embedded into T-shaped grooves in the sliding plates. The head of a piston rod of the hydraulic cylinder is connected to the front end of the cross beam through a hinge. According to the horizontal positioning device, no vibration is produced in the extrusion process when the equipment is located in the horizontal state, and it is ensured that the product extrusion speed is stable and reliable, so that the product quality is improved, and high-quality electrodes are obtained through extrusion.