The organic light emitting diode(OLED)was fabricated,which uses graphen e doped in NPB as the hole transport layer.The structure of the device is ITO/NPB:Graph ene(20wt.%) (50nm)/Alq₃(80nm)/LiF(0.5nm)/Al(120nm).We compare it with the standard device whose structure is ITO/NPB(50nm)/Alq₃(80nm)/LiF(0.5nm)/A l(120nm). The effect of graphene on performance of OLED is investigated.The results show that the device with graphene doped NPB layer presents better performance under t he same conditions.When the current density is 90mA/cm²,the current efficiency reaches the maximum value of 3.40cd/A,and compared with the standard device,the maximum efficiency is increased by 1.49times.The devic e reac hes the maximum luminance of 10070cd/m²when the dr iving voltage is 15V,which is increased by 5.16times than that of the standard device.