A method to deposit a new configuration of thermochromic VO2 films material was described, By ion beam sputtering and annealing in reductive ambient, VO2 films grown onto the glass substrate show an abrupt phase transfomation. Nanometer-scale VO2 grains are found under HRTEM and XRD observation. Four-point-test shows that the films phase transition temperature has shifted towards room temperature. The transmittances measured on different temperatures also reveal that the material owns excellent switching response to infrared light at critical transition temperature. A design of SiO2 anti-refection coating is used to improve low visible transmittance of the films, which obtains a satisfying result in experiments. It is a basic study in the applications of VO2 films to smart windows.