Flexible organic light-emitting diode(FOLED) with a structure of Ag/MoOx/HIL/organic layer/LiF/Al/Ag/Alq3 is fabricated.By adjusting the film thickness of hole injection layer(HIL),the cavity length is changed to regulate the microcavity effect,and then a highly efficient microcavity FOLED is obtained.By performance optimizing,a device structure of the top-emitting microcavity FOLED for full color display using Ag as the anode is achieved,and the thicknesses of HILs for blue,green and red FOLED are 100 nm,120 nm,and 160 nm,respectively.