The invention relates to a PS composite material, which comprises the following components in parts by weight: 80-90 parts of PS; 5-10 parts of ASA; 6-12 parts of PS-g-AN; 12-18 parts of heat conducting fillers; and 0.1-0.5 part of an antioxidant. When a blend of PS and PS-g-AN is irradiated by ultraviolet rays, -CN in the PS-g-AN can absorb ultraviolet energy; after the energy is obtained, the -CN can preform a transition reaction from a ground state to an excited state; and as the excited state is unstable, the -CN returns to the ground state, and energy is released. In the blend of PS and PS-g-AN, the PS-g-AN absorbs ultraviolet energy, and releases part of ultraviolet energy through the reversible process of ground state-excited state, and thus the damage of ultraviolet light to a PS basal body is reduced.