Yellow phosphorescent organic lighting emitting devices were fabricated by using green phosphorescent dye GIr1and red phosphorescent dye R-4B doped with the host mat erial CBP as the emitting layer. The structure of the devices is ITO/MoO₃(60nm)/NPB(40nm)/TCTA(x nm)/CPB:GIr1:R-4B(30nm,14%,2%) /BCP(10nm) /Alq₃(40nm)/LiF (1nm)/Al(100nm),in which x is equal to 0,5,10and 15.The current efficiency of yellow phosphorescent organic lighting emitting devices has been i mproved by inserting TCTA as an electron blocker between the emitting layer and the hole transport layer.It is f ound that the best thickness is 10nm for the TCTA layer,the turn-on voltage of this device is 4V,the highest current effi ciency is 20.2cd/A,the highest luminance of the device is 21840cd/m²,the commission inter nationale de I′Eclairage (CIE) color coordinate is (0.42,0.53) and the EL spect ra show two prominent peaks at 524nm and 604nm.Moreover,at a current density o f 2.49mA/cm²,the current efficiency of the device with 10nm-thick TCTA as the electron blocker layer is approximately two times greater than that of t he device without TCTA layer.The current efficiency of device is enhanced becaus e of an electron blocker confining the emitting of NPB,which leads to more excit ions combining in the emissive layer.