In the ytterbium ion optical clock experiments, the ions are cooled and manipulated by lasers, and the laser frequency shifts will affect the atomic clock system. Aiming at the laser frequency shifts, based on the digital PID control method, a new multi?channel frequency?digital signal conversion method for frequency stabilization is designed to lock the multi?channel and multi?wavelength laser frequency to the reference frequency of the wavelength meter. The laser frequency data before and after locking are acquired for a certain amount of time and compared. The result shows that the laser frequency drift is stabilized from 800 MHz to ± 0.8 MHz, the laser frequency short?term instability decreases from 9.29 × 10^-10@1 s to 2.79 × 10^-10@1 s, and the long?term instability reaches 3.85 × 10^-12@1 000 s. The system is simple and easy to implement, and has the advantages of miniaturization and strong adaptability.