In this work,based on the fundamental device of ITO/MoO₃/NPB/Ir(ppy)₃/TPBi/Cs₂CO₃/Al,devices with structures of ITO/MoO₃/NPB/Ir(ppy)₃/NPB(spacer)/TPBi/Cs₂CO₃/Al and ITO/MoO₃/NPB/TPBi(spacer)/ Ir(ppy)₃/TPBi/Cs₂CO₃/Al were fabricated.The effect of the spacer thickness on exciton recombination zone is investigated by analyzing electroluminescent (EL) spectra.The experimental resu lts indicate that the exciton recombination zone of all devices are located in NPB and Ir(ppy)₃.The recombin ation zone shifts towards NPB with the increase of the applied voltage and spacer thickness.As the thickness of NPB spacer increases from 0nm to 10nm,Commission Internationale de L′Eclairage (CIE) coordinates are equably ch anged,and its variation,Δ(x,y) is less than (0.02,0.10) .For the devices with TPBi as a spacer,Δ(x,y)<(0.04,0.20).When the thickness of TPBi spacer is no more than 6nm,the evolution of spec tra with the thickness is negligible,which leads to narrow adjustment range.Whe n the thickness of TPBi spacer is 10nm,the shift of spectra is greater.That is, it is a simple and convenient approach for changing the spacer and its thickness to manipulate the exciton recombination zone.This provides a guidance for the rough or fine tuning of emission intensity from dif ferent zones and the design of white organic light-emitting diodes (OLEDs).