The invention discloses a method for modifying plastic particles with a graphene oxide stock solution. The method is characterized by comprising steps as follows: 1), preparation of the graphene oxidestock liquid: graphite is taken as a raw material and subjected to sulfuric acid oxidation, potassium permanganate oxidation and hydrogen peroxide oxidation in sequence, and the graphene oxide stocksolution is obtained; 2), preparation of the graphene modified plastic particles based on a screw extrusion method: a plastic wire material extruded from a plastic substrate is soaked in the grapheneoxide stock solution obtained in the step 1), the soaked plastic wire material is granulated and dried, and the graphene modified plastic particles are obtained.