The diamond-like carbon (DLC) film is deposited by radio frequency plasma-enhanced chemical vapor deposition (rf-PECVD) on silicon (100) wafers. Methane (CH4) and hydrogen (H2) were used as the precursors. The effect of the rf power on the properties of the DLC films was investigated.Raman spectra were recorded by using a JY-HR800 spectrometer with 532 nm laser excitation line and 5 mW output power. The x-ray photoelectron spectroscopy (XPS) was used to determine the sp3 content. The hardness and Young"s modulus of the films were measured by means of nano-indenter. The morphology and roughness of the thin films were studied with an atomic force microscope (NanoScope â…¢a/AFM).The root mean square (RMS) roughness of the film is only 0.157 nm, therefore, the surface of the films is uniform and smooth. The hardness, elastic modulus and the fraction of sp3 bonding increase with rf power, which reach the maximum level at 100 Watts. Then the hardness, however, decreases to 9.96 GPa at 400 W. This indicates that the films transform to graphitic at higher power.