Nonvolatile ternary memory devices were fabricated from the composites polymer blends containing zinc oxide (ZnO) nanoparticles. When applying a negative bias on the top electrode, the fabricated devices with a simple sandwich structure of indium tin oxide (ITO)/composite polymer/aluminum (Al) exhibited three distinct resistance states, which could be labeled as "OFF", "ON1" and "ON2" for ternary data storage application. The ITO/polystyrene (PS) + ZnO/Al devices can endure 3 × 104 read-cycles and exhibit a retention time of 104 s. The resistance-temperature dependence at different resistance states was investigated to confirm the temperature-dependent properties. The resistance of the "OFF" and "ON1" state reveals negative temperature dependence, manifesting a typical semiconductor characteristic. The resistance of the "ON2" state exhibits positive temperature dependence, showing metallic properties.