The invention discloses a low-odor low-VOC (volatile organic compound)-content styrene polymer composition and a preparation method thereof. The composition is prepared from the following components in percentage by weight: 70-99% of styrene polymer, 0.5-29% of strippant master batch and 0.01-1% of antioxidant. The preparation method comprises the following steps: preparing a strippant master batch, mixing the components in a high-speed mixer, adding the mixture into a screw extruder, carrying out melt extrusion, and granulating. The invention has the advantages of simple production technique and lower production cost, and effectively lowers the order and VOC content of the styrene polymer; and the prepared styrene polymer composition can be used in the field of materials with strict environmental requirements in packaging materials, daily necessities, home appliances, OA, toys, sports equipment, shoe materials, cables, instruments and meters, electronic components and equipment, construction materials and automobile materials.