The electxonluminesence characteristic of single-layer light emitting device with a novel bipolar transport material is reported. Oxadiazole-containing triphenylamine polyme was used as the emitting layer. ITO and Mg/Ag were used as electrodes.The device emitted a bright green light ,with 5 V of turn-on voltage ,and it exhibited a maximum luminance of 2015 cd/m2 and a maximum electroluminenscent efficiency of 0.93 cd/A.