High quality and stable silicon dioxide (SiO2) films are grown on gallium arsenide (GaAs) substrate by liquid phase deposition (LPD) method at room temperature, with specific emphasis on passivation layer application. The LPD SiO2 film is of uniformity less than the similar to1.2%. A maximum growth rate and refractive index of silicon dioxide of 1300 Angstrom /h and 1.423 are obtained, respectively. The leakage current of as-deposited SiO2 is 42 pA and the dielectric breakdown field is II MV/cm. The film quality demonstrates its potential in fabricating high-speed devices.