PET plastic toughening agent and preparation method thereof

The invention discloses a PET plastic toughening agent comprises the following components in parts by weight: 15-45 parts of PET, 12-28 parts of maleic anhydride grafted SEBS, 1-10 parts of a dispersant, 0.5-1.5 parts of a chain extender, 25-38 parts of MBS, 2-10 parts of a transparent nucleating agent, 3-6 parts of a phosphite stabilizer and 1-4 parts of diffusion oil. The mass fraction of the PET plastic toughening agent added into a PET product is 0.2-1%. The invention also discloses a preparation method of the PET plastic toughening agent. The PET plastic toughening agent disclosed by the invention does not influence the transparency of the PET product and can achieve a very good toughening effect on the PET product, and the toughness of the PET product is improved by 15-30%; a small amount of the PET plastic toughening agent is added and cannot influence the physical property of subsequent processing of PET; the PET plastic toughening agent is environmentally friendly and non-toxic, cannot generate a separation phenomenon for the PET product, is highly compatible with PET by taking PET as a base material, and can better act on the PET product.