The invention discloses a full decoupling annular micro gyroscope based on optical microcavities and a processing method thereof. The micro gyroscope comprises a cover cap and a wafer from top to bottom. The wafer comprises an upper apparatus layer and a lower substrate layer. The apparatus layer is provided with a plurality of electrodes, a harmonic oscillator, a first optical microcavity, a second optical microcavity, a first light wave guide and a second light wave guide. The electrodes are adjacent to the inner wall of the harmonic oscillator to form a capacitor; the first light wave guideand the second light wave guide are symmetrically distributed on two sides of the harmonic oscillator; the first and second optical microcavities are adjacent to the first light wave guide and the second light wave guide, separately, and the first and second optical microcavities are connected to the harmonic oscillator. By adopting an optical detection scheme, compared with a conventional micro-mechanical and electric gyroscope, the reliability and measuring precision of the gyroscope can reach a higher level.