Silicon doped vanadium dioxide films were successfully prepared on indium tin oxide coated glass substrates at 255°C annealing temperature by direct current magnetron sputtering. Maintaining spheroidal grains, the size of VO2 films nanoparticles decreased with silicon doping ratios increasing. Transmittance spectra indicated a 46nm blue-shift of absorption edge and improved the samples' integrated luminous transmittances (from 28.4% at Si/V=0 to 36.1% at Si/V=0.17) with similar thickness of 90nm. The samples presented excellent thermochromic properties that possessed higher than 40% near-infrared switching efficiency at 2000nm and showed at least 9.2% solar modulation efficiency. Moreover, the metal–semiconductor phase transition temperature for heavily doped VO2 (Si/V=0.17) decreased to 46.1°C (22°C lower than bulk). These features suggest the practical application of VO2 to smart windows.