Numerous EVs have been integrated in power grid, which will not only can be used as controllable load, but also can be used as a distributed storage unit to provide auxiliary service. Frequency response control strategy of EV distributed storage is proposed considering aging of battery, which have been rarely discussed by researchers. This strategy can satisfy the individual demand of users ’ individual demand and SOC constraints, avoid exceeding the state of charge limit or damaging the battery caused by the large charge-discharge current. A simulation study is carried out to demonstrate the electric vehicle for frequency regulation as mobile energy storage unit. The simulation results showed that control strategy of distributed storage greatly suppressed system frequency deviation, mitigating ageing of EV power battery.