Fluorinated diamond_like carbon(F_DLC) films were prepared by radio frequency(RF) reactive magnetron sputtering with trifluoromethane (CHF3) and argon as source gases, and pure graphite as a targ et. The influence of source gas flow rate ratio on the film bonding configuration, sp2/sp3 hybrid ratios and optical band gap were investigated by Raman, Infrared transmission spectra, UV_visible spectra and XPS spectra. The results show that F-DLC films with high fluorine content, wide optical band gap and ultra-low diel ectric constant can be prepared by RF reactive magnetron sputtering technique in low input RF power (60W), high pressure (2.0Pa) and proper sour ce gas flow ratio (Ar/CHF3=2∶1).