Abstract: With the rapid development and promotion of new power systems, the increasing frequency regulation pressure faced by thermal power units has led to the proposal of a flywheel-thermal power primary frequency control strategy using successive variational mode decomposition. Firstly, taking the flywheel energy storage and thermal power units as the research objects, a flywheel-thermal power primary frequency control model considering the proportion of new energy sources is established. Secondly, the primary frequency control power command is decomposed using the successive variational mode decomposition method, with the thermal power units responding to the decomposed low-frequency power command.At the same time, an optimized control method for flywheel energy storage droop is designed to achieve the coordinated control of flywheel energy storage and thermal power unit response to frequency changes. Finally, simulation verification under different operating conditions indicates that the proposed strategy effectively avoids frequent output changes during the primary frequency control of thermal power units, reduces the control requirements for thermal power units responding to frequency changes, and maximizes the utilization of flywheel energy storage frequency regulation capacity while ensuring the operational safety of flywheel energy storage during frequency regulation periods, further enhancing the system’s frequency response capability.