White organic light-emitting device (WOLED) based on fluorescent sub-monolayer combining with phosphorescent doping layer is fabricated, in which fluorescent material 4,4′-bis(2,2′-diphenyl vinyl)-1,1′-biphenyl (DPVBi) acts as blue emitter layer, sub-monolayer ［2-methyl-6- ［2-(2, 3, 6, 7-tetrahydro-1H, 5H-benzo［ij］ quinolizin-9-yl) ethenyl］-4H-pyran-4-ylidene］ propane-dinitrile (DCM2) inserted in the blue emitter layer acts as red emitter layer, fac tris (2-phenylpyridine) iridium ［Ir(ppy)3］ doped into 4,4′-N,N′-dicarbazole-biphenyl(CBP) host acts as green emitter layer, respectively. The structure of device is ITO / NPB（40 nm ）/DPVBi (8 nm) /DCM2(d)/CBPIr(ppy)3 8% (15 nm)/4, 7 -diphenyl-1, 10-phenanthroline (BPhen) (60 nm)/LiF (1 nm)/Al (200 nm). The device performance is controlled by varying the thickness of DCM2. The maximum current efficiency and maximum luminance of the device with the DCM2 thickness of 0.05 nm DCM2 are 7.60 cd/A, 15 420 cd/m2, respectively. The commission international eclairage (CIE) color coordinates of the device vary from (0.34, 0.44) at 4 V to (0.27, 0.33) at 12 V. In order to further improve the performance of WOLED, the BPhen is used as exciton block-layer to the WOLED, the maximum current efficiency and maximum luminance of the device with BPhen thickness of 5 nm are 10.56 cd/A at 4 V, 25960 cd/m2 at 13 V, respectively. The CIE color coordinates of the device vary from (0.34, 0.44) at 4 V to (0.28, 0.36) at 12 V that are general within the white region. The results show that, compared with that of without exciton block- layer, the devices employing exciton block-layer yield higher device performance as well as comparatively stable electroluminescence spectra and CIE color coordinates results stable white emission.