Carbon nanotubes (CNTs) cathodes have been made by using screen-printing. Conglutinated CNTs were separated after ablation by laser beam. The spacing between CNTs is increased， the screen effect is diminished. Experiment results show that the field emission properties of CNTs film are highly improved， the relevant turn-on voltage was reduced and the field enhancement factor β was enhanced. From Raman spectra of multi-wall CNT films treated by laser ablation， the defects on CNT surface were increased with increasing laser energy， and became new field emission dots. Compared with diode structure, the flat gate structure showed better field emission performance. So the laser ablation is an effective method that could enhance CNT field emission properties， and has value in the research of CNT cathode materials. At the same time， the flat gate structure has better prospects in the structure design of CNTs field emission flat display.