Lowering down the driven voltage can b enefits to the luminous efficiency and the lifetime of the organic light-emitti ng device (OLED).To further decrease the hole injection barrier from the ITO ano de surface to the hole transport layer is a effective way to lower down the driv en voltage.In our work,a double hole injection layer (D-HIL) consisting of CuI/ CuPc was adopted into a CBP:BCzVBi blue emitter device to increase the hole inj ection efficiency.Comparing with the reference device with the single HIL layer of CuPc,the turn-on voltage of 3.4V was obtained in the D-HIL which lower 0.4V than the reference device,and the Current Efficiency (CE) was improved 19% at 20mA/cm2along with the driven-voltage lower down 0.9V than the reference de vice.The Fowler-Nordheim (F-N) tunneling theory was adopted to analyze the imp act of hole injection barrier on the hole injection electricity current density, it can be found that the hole injection electricity current density for the D-H IL device was improved via a stepped energy level which means a more facilitated hole injection efficiency,and hence the driven electricity current along with t he CE were improved.As a result,a clearly improvement in the CE and driven-volt age had been obtained in the D-HIL.