This paper investigated a high efficiency stacked white fluorescent organic light-emitting diodes consisting of separate blue and yellow elements with a 1,4,5,8,9,11-hexaazatriphenylene-hexacar bonitril (HAT-CN) hole injection layer. The configurations of the devices are ITO/2-TNATA or HAT-CN(x nm)/NPB (25 nm)/ADN (30 nm)∶TBPE (2%)∶DCJTB(1%)/Alq3 (20 nm)/LiF (1 nm)/Al (100 nm). According to the experimental result, the effect of HAT-CN film on carrier injection and color purity were significant. This work obtained a higher efficiency and color purity for the WOLED with HAT-CN layer, as compared to the conventional devices with copper phthalocyanine (CuPc) or 2-TNATA materials as a hole injection layer. It shows pure-white light emitting with 1931 CIE chromaticity coordinates x=0.330 9, y=0.347 2, and a current efficiency of 6.4 cd/A.