Abstract: This paper proposed an optimal power control strategy of AC excited pumped energy storage unit considering the influence of unit loss and speed. Firstly, this paper analyzed the sources of power loss in the power generation and pumping modes, and obtained the expressions of electromagnetic power and mechanical power considering the influence of loss and speed. Then, considering the influence of rotational energy, the adjustment ability of different power control strategies based on step change and slope change is analyzed, and the optimal power coordinated control strategy of doubly-fed pumped energy storage was obtained. Finally, a semi-physical simulation platform was constructed to simulate and compare the different active power step modes of pumped ebergt storage units under power generation and pumping conditions. The results showed that the control strategy proposed in this paper can optimize the coordination between governor and excitation control. Compared with the traditional method, the power regulation rate of the proposed method is faster and the response to the power command of the power grid is faster and more accurate. It also effectively alleviated the problem of new energy consumption and primary frequency regulation caused by new energy sources such as wind power.