The gyroscope operation relies on the electrostatic actuation and capacitance detection between the resonator and the planar electrode, with a typical gap ranging from 20–150 μm. When organic impurities adhere to planar electrode’s surface, gap’s capacitance changes, leading to fluctuations in the excitation detection signal and thereby affecting the accuracy and reliability of the gyroscope. TiO2 thin film can effectively degrade organic pollutants through photocatalytic reactions. However, little research on its application on the surface of high-precision devices has been reported yet. The thickness of the TiO2 thin film affects the generation and effective separation of photo-generated electron-hole pairs, thereby influencing the photocatalytic performance of the TiO2 thin film. It is thus necessary to determine the thickness of the TiO2 thin film on the surface of the planar electrode through experiments. In this paper, a TiO2/Au composite thin film was designed to reduce the adsorption of organic substances on the surface of planar electrode and improve the thin film quality on the planar electrode surface.