Abstract: VO2 thin film with good thermochromic properties have been prepared by controlling annealing time and annealing temperature in vacuum.The structural,optical and electrical properties of samples prepared at different parameters have been characterized by using techniques of XRD、XPS、UV-VIS and electrical measurements.The results show that before and after phase transition the resistance of VO2 thin films change about 103 orders,the transmittance of 900nm light change 40; and the switching velocity for absorptivity at 900nm is about 0.2607/min.The structural properties of samples have been improved while the phase-transition properties have declined with the increase of annealing time and annealing temperature.The valence of V and structure of samples have great effect on phase-transition properties of VO2.The best reasonable annealing time and annealing temperature has been got by discussing the effects of annealing time and annealing temperature on the phase-transition point,hysteresis width.