The sky-blue phosphor FIrpic-based electrophosphorescent bottom-emitting metallic microcavity organic light-emitting device(OLED) employs a structure of glass/Al(15 nm)/MoO3(x nm)/NPD(40 nm)/ mCP:FIrpic(30 nm,7%)/BCP(20 nm)/Alq3(20 nm)/LiF(1 nm)/Al(150 nm),using MoO3 and LiF as efficient hole and electron injection layers,respectively.The cavity structure consists of the highly reflective Al cathode and the semitransparent Al anode.The emission spectrum of the microcavity OLED is centered at 468 nm with a full width at half maximum(FWHM) of 24 nm,and CIE color coordinates are x=0.14 and y=0.15.It′s indicated that the spectrum is modulated and narrowed.Theoretical simulations of the enhancement factor of the microcavity OLED agree with experimented results well.