Nanostructured carbon thin films on Si tips were prepared by hot filamentchemical vapour deposition at different substrate temperatures. The Si tipsand films were obtained under various deposition conditions in the same reactionchamber. It was found that the field emission properties from graphite-likenanostructured carbon on Si tips were greatly improved, compared withthose of nanodiamond films on Si tips. A turn-on field of 1.2 V·cm-1 wasobserved for high sp2 content thin films on Si tips. The analysisshowed that the field emission enhancement effect was caused by the tipgeometry, tunnel effect and sp2 content in the films. However, thegeometrical enhancement was greater than that of the tunnel and sp2content effects.