VO2-based "smart window" could respond to temperature variation and change its near-infrared transmittance automatically without obvious change of visible light transmittance, so as to regulate the infrared energy of sunlight.Among various structures of VO2-based films, VO2 nanocomposite films have the best synergetic optical properties, but they still have some disadvantages on solar energy regulating property for practical usage.Based on high quality VO2 nanoparticles prepared by hydrothermal reaction, this work had conducted an in-depth study on the annealing process and performance optimization methods of VO2-TiO2 nanocomposite film through research of TiO2 film preparation, and successfully acquired the VO2-TiO2 nanocomposite films with excellent thermochromic-electrochromic properties.