Vanadium dioxide (VO2) is a kind of thermochromatic material. When phase transformation occurs, its resistance, optical transmittance and reflectivity will be changed obviously. Some preparing parameters, such as gas flow ratio of argon to oxygen, sputtering atmospheric pressure and substrate temperature, are changed by using a direct current reactive magnetron sputtering method. The effect of those preparing parameters on the structure and resistance-temperature characteristics of a VO2 film is studied. The result shows that when the ratio of argon to oxygen is 1.0∶15 and the gas pressure is 2.0Pa, the prepared film contains more VO2; and when the substrate temperature is 250℃, the prepared VO2 film has its best resistance-temperature abrupt capability.