Aiming at the problem of resonant frequency drift of Resonant Micro-optical Gyros (RMOG) due to factors such as ambient temperature and vibration, this paper proposes a high-precision digital frequency locking and error feedback technology research program based on FPGA. The system realizes dual-phase modulation and frequency difference signal processing through FPGA, combines 20-bit digital-to-analog converter AD5791 to generate high-precision feedback signals, uses PI controller to complete real-time tracking and locking of laser frequency to the resonant cavity of the optical waveguide, and introduces real-time output compensation algorithm based on the error feedback to dynamically correct the output loop deviation. The experimental results show that the response time of the frequency locking system is 17.5 ms, and the frequency locking accuracy reaches 48.51 Hz, which significantly improves the dynamic performance and stability of the gyro system. Compared with the traditional 16-bit DAC scheme, the new system improves the response speed and frequency locking accuracy by 62.3% by 56.0%, which verifies the effectiveness of the digital architecture and the dual-phase modulation technique in suppressing the noise and optimizing the spectral separation, and provides reliable technical support for the practical application of the resonant optical microcavity gyro.