Abstract: The safe and stable operation of power systems requires more high-quality power regulation resources to be applied in frequency regulation auxiliary service market. Due to the vacancy of rules on reimbursement for battery energy storage system(BESS) alone in China, the combination of thermal power unit and BESS for the AGC frequency regulation get commercial promotion. The AGC performance evaluation index comprehensively reflects the system frequency regulation requirements. Therefore, a time-period partitioning storage control strategy considering performance evaluation standard of AGC power unit was proposed. The timing and depth of storage action were reasonably controlled in different periods, containing initial, climbing, stable and non-assessment periods. Compensation revenue improvement and construction costs reduction were verified with simulation based on measured data. The 9.6MW/4.8MW·h BESS project in a power plant at Guangzhou, China, further verified the practicability of the proposed control strategy, which improved the performances by 3~4 times, increased the capacity by 10%~20% and compensation revenue by 10~15 times for the plant comparing with other strategies.