The compulsory material feeding device of the plastic recycling machine includes a reduction gear box, a screw outer cylinder and a forced screw. The forced screw is tapered along the material conveying direction and is located in the outer cylinder of the screw. The inner wall of the outer cylinder of the screw is matched with the shape of the forced screw, and the feed port is provided on the outer cylinder of the screw. The forced feeding device solves the problem that the original plastic recycling machine has no low-bulk density loose material due to no mandatory feeding device, thereby resulting in the problems of insufficient host productivity, low efficiency, high cost, and poor economic efficiency, and has a design structure. Simple, low cost, easy to install and use, and easy to promote, can be used for a variety of plastic recycling machines.