We demonstrate a novel polarization control system based on a gradient descent algorithm,applied to a 450-km optical frequency transfer link.The power of the out-loop beat note is retrieved by controlling the polarization state of the transferred signal,with a recovery time of 24 ms,thereby ensuring the long-term evaluation of the fiber link.As a result,data utilization is enhanced from 70％ to 99％ over a continuous measurement period of～12h.A fractional transfer instability of 7.2 × 10-20 is achieved at an integration time of 10000s.This work lays the foundation for the comparison of a remote optical clock system via a long-haul optical fiber link.