The invention discloses a plastic extruder screw electromagnetic heating structure which comprises an extrusion barrel and an extrusion screw arranged in the extrusion barrel. The extrusion screw stretches out of the extrusion barrel to be connected with a driving device. The end, close to the driving device, of the extrusion barrel is provided with a feed inlet, and the other end of the extrusion barrel is provided with an extrusion outlet. Heat preservation rock wool is arranged outside the extrusion barrel. Multiple sets of induction coils are wound outside the heat preservation rock wool. Each set of induction coils is connected with a corresponding controller. An upper pressing plate is arranged at the upper ends of the induction coils and stretches out of the two ends of the induction coils to be connected with the heat preservation rock wool through upper pressing screws, and a lower pressing plate is arranged at the lower ends of the induction coils and stretches out of the two ends of the induction coils to be connected with the heat preservation rock wool through lower pressing screws.