Abstract: To effectively enhance the active support capability for frequency in respect of the generation side of the power grid, and improve the stability, safety, and economy in respect of the operation of thermal power units, the primary frequency regulation of thermal power unit assisted by hybrid energy storage was taken as the main research object, while an optimized coordinated control strategy was proposed. Firstly, a coordinated control model of the combined system of thermal power and storage was established, and the primary frequency regulation signal of the thermal power unit was decomposed to alleviate the frequent load adjustment actions of the unit. Secondly, the energy storage control strategy was optimized. Adaptive weighting coefficients were output using a fuzzy control method, enabling smooth switching between droop control and inertia control, thus enhancing the capability of frequency regulation. Finally, a hybrid energy storage capacity optimization configuration model was constructed, and the economic benefits of different control strategies were analyzed using whale optimization algorithm. Results indicate that under continuous disturbances, the overall deviation of the system frequency of the proposed control strategy is reduced by 23.33% and 11.54% compared with that of the variable K method and droop-inertia control, respectively, while the average output of thermal power unit is decreased by 35% and 23.53%, respectively. This effectively improves the performance of frequency regulation of the combined system of thermal power and storage, enhances economic benefits, and facilitates the safe and stable operation of thermal power units.