For a typical controllable load electric vehicle, a charge and discharge control strategy based on virtual synchronous machine technology is proposed. The two-stage topology is used for the research. The fore-stage AC/DC control introduces a new virtual synchronous machine technology based on the charge and discharge mode, so that the electric vehicle has the similar inertia, damping, frequency and voltage regulation characteristics of the traditional synchronous machine. Meanwhile, the charging and discharging mode set in the control prevents the battery from being fully charged and discharged, and improves the service life; The double closed-loop control of the DC bus voltage is applied to the subsequent DC/DC control to improve the voltage stability of the DC interface. The characteristic of this control is that the virtual synchronous machine and the charge and discharge control are realized by the front-stage rectifier, which has good coordination. The typical calculations in MATLAB / Simulink platform show that under different initial battery states, different grid loads, and distributed power access conditions, the proposed control strategy enables electric vehicles to not only provide inertia and damping support to the grid, but also the grid frequency and voltage changes automatically adjust the active and reactive power to achieve bidirectional power adjustment, which can meet the needs of users and improve the dynamic stability of the grid.