Ga2O3 thin films were grown on quartz substrate by radio-frequency magnetron sputtering. The structure and optical bandgap of Ga2O3 films were characterized by X-ray diffraction and UV-Vis-IR spectroscopy, respectively. The photoluminescence (PL) spectra of Ga2O3 films were measured at room temperature. The results show that the deposited Ga2O3 films are amorphous, the optical band gap becomes bigger. As the pressure increases, the optical absorption edge firstly shows blue shifted and then switches to red shifted. The optical bandgap value ranges from 4.96-5.30 eV. Under the excitation of 325 nm laser, luminescence peaks related to defect energy levels appear at 400 nm and 525 nm.