In this research, the germanium dioxide GeO2 was prepared using vacuum evaporation technique onto substrate (Microscopic glass and silicon wafer ) mounted on the substrate holder at 45 cm above the evaporation boat. Germanium oxide GeOx also evaporated using |reactive evaporation techniques It was achieved by evaporating germanium in oxygen at various partial pressure. Structural investigation were carried out by using X- Ray diffraction. It was found that the prepared samples were amorphous even after thermal annealing. The optical energy gap Eg for GeO2 and GeOx thin films obtained from transmittance data are measured in high absorption region. The allowed direct, forbidden direct and allowed indirect transition occur in GeO2 and (7c'0v.The optical energy gaps for films deposited at room temperature that are associated with allowed direct forbidden direct and allowed indirect transition are 3, 2.1, and 1.7eV respectively for GeO, and for GeOx 2.4- 2.6,1.2- 1.3 and 0.6- 0.8 respectively in oxygen pressure (3x10- 4- 2.3xl0-4 torr). It was found that the energy gap increased for GeO2 and decreased for GeOx after annealing.The band tailing of localized states in GeO2 was obtained from transmittance data in low absorption region and found to be (0.64, 0.71, 0.625, and 0.8eV) for thicknesses (100, 150, 510, a ad 1040nm Respectively. Annealing the films led to an increase in ihc oand tailing. The AC conductivity was measured in the temperature range (288- 370K) and it was found to be increased with frequency and follows the σ ∞ ω where s is temperature dependent. Tangent of loss angle, real part and imaginary part of dielectric depend on low frequency and becomes small enough to be neglect at high frequency, therefore the energy loss in sample under study becomes very little, so the capacitor prepared in this work have good stability at high frequency at different temperatures.