Abstract: Blends of ethylene-vinyl acetate-carbon monoxide terpolymer (Elvaloy)/modified poly(vinyl chloride) (PVC) were prepared in a two-roll mixer via melt blending. The effects of content of Elvaloy on transparency, cold resistance, micro-morphological structure, mechanical properties, and plasticizing temperature were studied. It showed that the transmittance of PVC/Elvaloy blends was above 76 %, and the haze was lower than 21 %. Because of the addition of Elvaloy, the low-temperature impact strength of PVC increased twice as much, elongation at break increased, and brittleness temperature and plasticizing temperature decreased more than 20 ℃ and 10 ℃, respectively. When the contents of Elvaloy were 2, Elvaloy/PVC blends exhibited only one Tg, indicating the components were compatible. With increasing contents of Elvaloy, Tg of the blends decreased.