Abstract: A thin film of PEN polymer with electrical bistable states at room temperature was discovered.The grain size of the PEN thin film prepared by vacuum deposition is estimated to be less than 100nm with a roughness of a few nanometers, and this film shows a good thermal stability. The impedance of the film will change from a high impedance state to a low impedance state under an applied voltage of 3.5 V. The transition time is less than 20ns. This material is suitable for making high-density memory.