New spiro[fluorene-7,9'-benzofluorene]-based blue host material, 5-phenyl-spiro[fluorene-7,9'-benzofluorene] (BH-1P), was successfully prepared by reacting 5-bromo-spiro[fluorene-7,9'-benzofluorene] (1) with phenyl boronic acid through the Suzuki reaction. 5-(N,N-Diphenyl)amino-spiro[fluorene-7,9'-benzofluorene] (BH-1DPA) and diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]amine (BD-1) were used as dopant materials. 2,5-Bis-(2',2-bipyridin-6-yl)-1, 1-diphenyl-3,4-diphenylsilacyclopentadiene (ET4) and Alq 3 were used as electron transfer materials. Their UV absorption, photoluminescence and thermal properties were examined. The blue OLEDs with the configuration of ITO/DNTPD/α-NPD/BH-1P:5% dopant/Alq 3 or ET4/LiF-Al prepared from the BH-1 P host and BH-1DPA and BD-1 dopants showed a blue EL spectrum at 452 nm at 10 V and a luminance of 923.9 cd/m 2 with an efficiency of 1.27 lm/W at a current density of 72.57 mA/cm 2 .