In order to solve The frequency fluctuation caused by The output fluctuation of distributed power sources such as wind power generation and photovoltaic power generation and The large-scale load entering into The grid, The primary frequency modulation control strategy of ev load clustering in The power grid was studied based on The V2G technology under The hot standby condition of The Electric car. The load of electric vehicles was classified according to the quick response performance of electric vehicles, and the load of electric vehicles was divided into different frequency modulation capacities by clustering algorithm. When the system frequency changes, the electric vehicle participates in the primary frequency modulation response of the power grid. The simulation results show that when the frequency of the power grid fluctuates, the electric vehicle participates in the primary frequency modulation of the power grid, which makes the power grid frequency quickly recover to a stable state. The proposed ev load clustering strategy is effective in frequency modulation control.