With the increasing penetration of renewable energy, automatic generation control (AGC) capacity requirements will increase dramatically, becoming a challenging task that must be addressed. The rapid growth of electric vehicles (EVs) provides new approaches for the stable operation of power systems. Vehicle-to-grid (V2G) technology has the potential to provide frequency regulation (FR) services. Fully taking into account the advantages of EVs and battery energy storage stations (BESSs), i.e. rapid response and large instantaneous power, this paper presents a coordinated control strategy for large-scale EVs, BESSs and traditional FR resources involved in AGC. Response priorities and control strategies for the FR resources vary with different operating states. To verify the effectiveness of the proposed control strategy, dynamic simulations for EV/BESS to participate in AGC of a two-area interconnected power system are performed in the Matlab/Simulink program. The simulation results show that the proposed method can not only fully utilize the advantages of EV/BESS, but also achieve the coordination among different FR resources, thus improving the frequency stability and facilitating the integration of renewable energy.