In this study, the nanocrystalline diamond (NCD) films were carried out by microwave plasma chemical vapor deposition (CVD) with CH4/Ar/H-2 gas concoction on Si substrate at moderate temperatures. The characteristics of NCD films were evaluated using scanning electron microscopy, Raman spectroscopy, transmission electron microscopy, optical emission spectroscopy and optical contact angle meter. The analytical results revealed that C-2 radial was the dominant species in the deposited process. From TEM observation, the NCD films were formed via the etching of hydrocarbons and a small amount of H-2 content additive into gas mixture has improved the aggregation of the nucleation film to form the NCD films. The more hydrophobic surfaces imply that NCD films are the potential biomaterial in the application of article heart valve or stent. (C) 2010 Elsevier B.V. All rights reserved.