The Ti-Si-C nanocomposite film was deposited in gas mixtures of Ar and CH4 by middle frequency unbalanced magnetron sputtering Ti80Si20 composite targets. The microstructure of the film was investigated by X-ray diffraction, Raman spectrum and X-ray photoelectron spectroscopy. The results show that the film exhibits nc-TiC/a-C:Si:H nanocomposite structure with about 10 nm nanocrystallites TiC embedded in hydrocarbon (a-C:Si:H) matrix. The results of XPS analysis strongly depend on Ar+ sputter-etching. The C and O content on the film surface distinctly decreases, while the Ti and Si content gradually increase with the increasing of Ar+ sputter-etching time. It is found that Ar+ sputter-etching results in the graphitization of the amorphous carbon phase in the nanocomposite film. In other words, the sp3C-C(H)/sp2C-C ratio decreases with the increasing of Ar+ sputter-etching time. In addition, the C-Ti*/C-Ti and C-(Ti+Ti*)/C-C ratios obviously increase.