Carbon-doped titanium monoxide films were successfully fabricated using CO2 as reactive gas by means of DC reactive magnetron sputtering. Phase tructure, composition and resistivity of the fabricated films were investigated by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and four point probe method. Results show that the fabricated film has a cubic phase structure, and the carbon element exists mainly as anion in the lattice of C-TiO. The resistivity of C-TiO is 52.2 μΩ·cm which is lower than that of pure TiO. Results of first principles calculation show that the Fermi levels of both TiO and C-TiO lie in their conduction bands, thus TiO and C-TiO have characteristics of metal conduction. Also the results of first principles calculation show that impurity levels of C 2p lie near the conduction band of C-TiO, which extend the width of conduction band and increase the density of states near the Fermi level of C-TiO, so the conductivity of C-TiO is larger than that of undoped TiO. The theoretical calculations are in agreement with experiment results.