Negative ion paint additive is characterized in that, wherein contains (weight %): tourmaline superfine powder 40-60, nanometer TiO 2 Photocatalytic powder 0.5-5, topaz superfine powder 2-35, TiO 2 and / or SiO 2 Ultrafine powder (residue), and the above-mentioned tourmaline ultrafine powder has been processed through electron beam activation intensification in advance, and the conditions of this treatment are: electron beam accelerating voltage 10-50kV, electron beam current 100-200mA, electron beam irradiation area 2-10cm 2 , The thickness of the powder is 0.5-2cm, and the longitudinal movement speed of the powder is 0.5-2m / min. The negative ion coating additive of the present invention has strong negative ion generation ability, so its consumption is small, the effect is high, and there is no radioactive hazard. At the same time, it can effectively remove formaldehyde, ammonia, benzene, VOC and other odorous gases.