Waste plastic treatment method and device

The invention provides a waste plastic treatment method and device. The invention provides a waste plastic treatment method which is carried out by adopting an extrusion unit, a first cracking unit and a second cracking unit which are communicated in sequence, and in the treatment process, the waste plastic is firstly pretreated, and the pretreated waste plastic is input into the extrusion unit for extrusion treatment; then, the first material output by the extrusion unit is input into a first cracking unit for low-temperature decomposition; and carrying out second cracking treatment in a second cracking unit loaded with the FCC waste catalyst to obtain a treated product. According to the method provided by the invention, the yield of the pyrolysis oil can be improved, the chlorine content in the pyrolysis oil can be reduced, the pressure and load of subsequent refining can be reduced, the requirement limitation of downstream procedures on the distillation range and property of the pyrolysis product can be me