Abstract: The large-scale integration of renewable energy imposes higher requirements on the frequency regulation capabilities of thermal power units in modern power systems. Coupling flywheel energy storage with thermal power units can effectively enhance their frequency regulation performance, thereby supporting the development of next-generation power systems. This paper first introduces the fundamental principles and structure of flywheel energy storage systems, and analyzes the basic mechanisms of their integration with thermal power units for frequency regulation. The current research status of control strategies for flywheel-assisted thermal power unit frequency regulation is then systematically reviewed. Finally, the key challenges and open issues in existing control strategies are discussed, providing directions for future research.