Abstract: Aiming at the power grid security problems caused by the competitive charging behavior of large-scale electric vehicles under the dynamic electricity price mechanism, a congestion management model of electric vehicle aggregator considering power grid security constraints is proposed. Firstly, the lossless linearization model of distribution network and the cluster model of the electric vehicle aggregator are established. Secondly, a competitive game model among electric vehicle aggregators considering power grid security constraints is proposed under the dynamic electricity price mechanism. Thirdly, the existence of equilibrium solution and the uniqueness of variational decomposition of the game model are proven based on the theory of variational inequality.Finally, the gradient descent algorithm and the proximal decomposition algorithm are used to solve the proposed game model.Numerical results show that the proposed model can ensure the power grid security when large-scale electric vehicles are competing for charging.