Carbon containing C_TiO2 nanoparticles with rutile mass fractions about 20%, carbon mass fractions from 0-22%, having normal size distributions with mean sizes from 24-62 nm are synthesized by the oxidation of TiCl4 in industrial propane/air diffusion flame. Photodegradation of VOCs of formaldehyde, benzene, toluene and methanol by the C_TiO2 nanoparticles have been investigated by using a tubular photoreactor with C_TiO2 thin films coated on the wall of the tubular reactor by a sedimentation method. Effects of effective thickness of C_TiO2 thin films from 60-150 nm, relative humidity from 8-100%, and initial concentration of VOCs loaded air stream from 0.06-3 g/m3 on degradation degree have been investigated. Comparisons are made on degradation degree between the C_TiO2 nanoparticles and P25 photocatalyst and the results show that the photocatalytic activity of the C_TiO2 nanoparticles and P25 are comparative.