WO3 thin film was prepared on glass substrate at room temperature by RF magnetron sputtering deposition with hybrid (Ar+2.5% H2) gas. Effects of RF power on the microstructure, electrical and optical properties of WO3 films are investigated by field emission scanning electron microscopy, X-ray diffraction, Hall measurement and spectrometer. X-ray diffraction analysis reveals that all of the films are amorphous. The minimum resistivity of the WO3 film prepared with RF 70W is 5.74 × 10-3 -cm. The average transmittance in the visible region was decreased with increased RF power from 50W to 150W. The average transmittance was lower than 15% with RF 50W. The electrical and optical mechanisms have been explained in terms of composition and film thickness were changed with RF power.