Diamond growth was carried out using various kinds of substrates and substrate holders in conventional microwave plasma-enhanced chemical vapor deposition with a mixture of CH4 and H-2 and the quality and electrical properties of the diamond films were investigated. The surface morphology and properties of the films were sensitive to plasma reaction with surfaces other than the growing substrate, in addition to the plasma/substrate chemical reaction and the external parameters for diamond growth. Nanocrystalline diamond films were deposited on silicon substrate by simply using graphite block as a substrate holder in the conventional reactor, with a mixture of CH4 and H-2 used for the formation of textured diamond films. The field emission characteristics of these diamond films were investigated. It was confirmed that small-grained films have a low emission threshold and a high emission current.