The structural properties of HfO2 films could be improved by calibrating the working pressure owing to the enhanced quality of a thin film. We deposited HfO2 films on glass substrates by radio frequency (RF) magnetron sputtering under a base vacuum pressure lower than 4.5×10-6 Pa, RF power of 100W, substrate temperature of 300°C. The working pressures were varied from 1mTorr to 15mTorr. Subsequently, their structural and optical properties were investigated. In particular, the HfO2 film deposited at 1mTorr had superior properties than the others, with a crystallite size of 10.27nm, surface roughness of 1.173nm, refractive index of 2.0937 at 550nm, and 84.85% transmittance at 550nm. These results indicate that the HfO2 film deposited at 1mTorr is suitable for application in transparent electric devices.