Abstract: The optical resonant cavity can not only enhance the interaction between the laser and matter, but also suppress the noise of the laser, which is an important tool for research on precision measurement, quantum optics, etc. Stable locking of laser and optical resonant cavity resonance is the key to its application. However, the locking effect will be affected by factors such as mechanical vibration, temperature changes, etc in the actual environment. The fuzzy algorithm is applied to the PDH (Pound-Drever-Hall) technology, so that the three parameters of the proportional-integral-differential controller can be adjusted according to the changes of the external environment to obtain the optimal parameters in real time, which effectively improves anti-interference ability of optical resonator locking. If outside interference is still so great that the lock is lost, the system can make it re-lock automatically. The system effectively improves the practicality of the optical resonator, and provides a technical basis for the application of the optical resonator in precision measurement and quantum optics experiments.