The invention discloses an improved disposed high impact-resistant polystyrene antiageing master batch. The master batch is prepared by the following steps: 75 to 95 parts by weight of disposed high impact-resistant polystyrene, 5 to 25 parts by weight of elastomer, 5 to 10 parts by weight of linearity low density polythene, 0.25 to1.0 part by weight of ultraviolet screening agent or/and chemicalinhibitor are added into a high speed mixer for mixing, and then into a double-screw extruder, and simultaneously 5-10 parts of styrene with 0.07 to 0.70 part of dissolved evocating agent and resin acceptor with the weight ratio being 1:1 are added from the glass fiber hole of the double-screw extruder, and then fusion and mixing are carried out at the temperature of 150 to 210 DEG C. The gap impacting intensity of the master batch is greatly increased, and the mechanics performance expense after aging experiment is lower than disposed HIPS alloy without ultraviolet screening agent or compound chemical inhibitor, and antiageing performance is ever better than that of HIPS new material, thus being used in producing office supplies, electron and electric, household electrical appliances, casing and the like, with apparent economic and social benefits.