Abstract: The establishment and growth of China's power system automation technology and smart grid necessitate enhanced precision and dependability in long-distance time-frequency transmission. Ground-based optical fiber timing has the advantages of strong anti-interference ability and high invulnerability due to its transmission medium. Combined with cascaded transmission technology, it can provide a solid guarantee for long-distance, high-stability and high-reliability frequency transmission. This paper detailly summarizes and analyzes the architecture and development status of optical fiber frequency cascaded transmission system at home and abroad in recent years, and looks forward to the future development trend of long-distance optical fiber frequency transmission technology and its application prospect in the power system, which will provide support for the construction of time-frequency synchronization network with satellite-earth mutual backup.