We have designed a high performance bule emission device by using the do ped Alq3 in hole transmission layers of NPB.According to traditional material and structure,we have designed the new structure of the device reasonably and increased the efficiency of blue light emission effectively and conveniently.The commission international CIE coordination of the devices is very stable at(0.17,0.19).The maximum electroluminescence efficiency is 4.1 cd/A at 11 V.The maximum brightness is 10 770 cd/m~2 at 13 V.Under equal conditions,the turn-on voltage also has reduced,the device luminance is 118.8 cd/m~2 at 7 V.The reason of these improvements is as follows:the HOMO level of the NPB is higher than that of the Alq3 at 0.3 eV,and the Alq3 molecule has scattering function to the hole,it has stopped the transmission of some holes,and reduced the mobility of hole;moreover Alq3 is a good material of electron and transmission,this adulterate can improve transfused balance of hole and electronic in the luminous layer,and it is beneficial to the formation of exciton,so it can enhance the capability of the device.