The microstructure and field emission properties of carbon nanotubes(CNT) grown by Ni-catalytic chemical vapor deposition(CVD) were investigated. CVD-grown CNT had a high density of curved shape with randomly oriented. It was found that an increase in electric field caused an increase in field emission current and field emission sites of CNT. The maximum field emission current density was measured to be 3.6 ㎃/$ extrm{cm}^2$ at 2.5 V/$mu extrm{m}$, while the brightness of 56 cd/$ extrm{cm}^2$ was observed for the CNT-grown area of 0.8 $ extrm{cm}^2$ from a phosphor screen. Field emission current at constant electric field gradually decreased initially and then stabilized with time.