The invention relates to the technical field of plastic production, and particularly relates to a plastic extruder. The plastic extruder comprises an extruder main body and a discharge conveying device, wherein the conveying device is provided with a frame; the frame is provided with a roller. The plastic extruder is characterized in that the roller is arranged perpendicular to the running direction of a pipe, and is connected with a power device; the side surface of the extruder main body is provided with a velometer connected with a controller; the power device is connected with the controller; a plurality of spherical rolling balls are embedded on the circumference of the roller. The plastic extruder has the advantage that when a pipe capable of reducing noise is produced by the plastic extruder, the product quality can be improved; the plurality of spherical rolling balls are embedded on the circumference of the roller, and the plastic extruder has the advantage of relatively good effect.