Proposed a frequency regulation strategy of electric vehicles based on hierarchical control theory.In the control structure,power grid was the main control center,it made the best frequency regulation result of the power grid as the control target,to coordinate the frequency regulation output between electric vehicles aggregators and generation companies;aggregators were the sub-control centers,it made the maximal profit as the control target when finished the frequency regulation task.To ensure the reliability and economy of the frequency regulation by electric vehicles,sub-control centers should made the’ comprehensive index’of electric vehicles higher.Sub-control centers should send frequency regulation plans to the main control center.Simulation results show that the control strategy not only can control electric vehicles finish the frequency regulation tasks,but also make the aggregators and users gain good profit.