The development of a miniaturized, digital, and high-bandwidth optical phase-locked control system is the key to realizing miniaturized narrow linewidth laser light sources for practical applications. However, current general-purpose and special-purpose systems have problems such as relying on commercial platforms, insufficient bandwidth, and low integration. The digital servo system developed is based on field programmable gate array (FPGA) and high-speed analog-to-digital converter (ADC) and digital-to-analog converter (DAC) to implement digital synthesizer, modulator,phase detector, filter and servo Control unit, successfully developed a high-speed, reconfigurable, dual-channel optical phase-locked loop integrated hardware platform, with a system open-loop bandwidth of 2. 63MHz. Combined with the whispering gallery mode (WGM) optical microcavity with high quality factor characteristics, a narrow linewidth laser with an integral linewidth of 20Hz is achieved through the phase modulation optical heterodyne frequency stabilization method (PDH), and the optical closed-loop feedback bandwidth reaches 450kHz. The system has good versatility and scalability, and can be applied to servo locking of various atomic and molecular spectra and optical frequencies.