Energy Storage (ES) participates in the control of a single scenario (peak regulation or frequency modulation) of the power grid, and the utilization rate is low. A peak-FM working area division method and cooperative control strategy based on ES State of Charge (SoC) are proposed. This strategy can realize ES switching between peak modulation and frequency modulation control, and then improve the utilization rate. Then, to further improve the effect of ES peak modulation, a variable power peak modulation strategy and integrated frequency modulation control strategy combining virtual inertia and droop control are proposed respectively in a single peak modulation scene. From here a cooperative control strategy of peak and frequency modulation is proposed. Finally, a simulation example shows that compared with monotone peak control and single frequency modulation control, the utilization rate of ES is improved by 16.25% and 37.29% respectively based on multi-timescale cooperative control strategy. This shows the feasibility of the method and strategy. This work is supported by the National Key Research and Development Program of China (No. 2017YFB0903400).