The invention discloses a control method for electric vehicle group to participate in power network frequency modulation, which comprises the following steps: a central processing unit divides a charging vehicle into different domains according to frequency deviation monitored by a power network frequency deviation measuring unit and electric vehicle information collected by a data acquisition unit of the electric vehicle entering the network; In the frequency modulation control domain, the frequency drooping control unit simulates the frequency drooping control principle of synchronous generator to obtain the frequency modulation power of the electric vehicle group response system, and the electric vehicle charge/discharge queue control unit controls the charge/discharge according to theup or down frequency modulation power; In the forced charge control domain, the maximum charging power of the electric vehicle forced charge queue control unit is forced to charge; The normal chargingand discharging arrangement of the normal charging and discharging unit of the electric vehicle in the uncontrollable charging and discharging area. According to the invention, the needs of the electric network frequency modulation capacity to the maximum extent can be met, and the traveling requirements of users can be also met.