Ag-CNT (carbon nanotube) composite cathodes are prepared on elaborate metal electrodes by electrophoresis and screen printing. The effects and conductive mechanism of nano-Ag on field emission properties of CNT cathodes are investigated. The morphologic images of nano-Ag film and Ag-CNT composite cathode are observed by scanning electronic microscopy (SEM). It is found that the nano-Ag particles are uniform and compact. The nano-Ag particles move to CNT cathode and fill up the contacting vacancy between CNT cathode and metal electrodes after co-sintered. So electronic transmission and heat transfer is improved between CNT cathode and metal electrodes. The experimental result show that the field emission properties, luminance and stability of CNT cathodes could be improved by the nano-Ag conductive film.