Abstract: Vertically aligned carbon nanosheets were synthesized on carbon fiber substrate by floating catalyst method.In this experiment,C₂H₂ was carbon source gas,N₂ was carrier gas and ferrocene was catalyst precursor.The products were characterized by scanning electron microscope（SEM）,energy dispersive X-ray spectroscope（EDX） and Raman spectroscope.The results show that after carbon fibers are immersed and boiled in the solution of ferrocene,sodium dodecylsulfonate（SDS） and acetone,the length and width of carbon nanosheets grown on carbon fibers are about 600 and 50 nm respectively.Raman spectrum indicates that carbon nanosheets have graphitic structure.The pretreatment of carbon fibers activates the surface and decreases the pervasion and absorption of catalyst into the carbon fibers.Based on the above results,carbon fibers/carbon nanosheets probably has important applications in field emission display.