The invention provides an electric energy bidirectional transmission system and a control method thereof. The system comprises a PWM voltage source type converter of two level topology structures, a DC bus capacitor Cdc and an isolation type bidirectional full bridge DC/DC converter. The DC bus capacitor Cdc is connected between the PWM voltage source type converter of two level topology structures and the isolation type bidirectional full bridge DC/DC converter, the decoupling and cascade connection of a first power circuit and a second power circuit are realized, and front and back level power circuits can work independently due to the existence of the DC bus capacitor Cdc. The electric energy bidirectional transmission between an AC grid and a DC bus is realized by the PWM voltage source type converter of two level topology structures, and the electric energy bidirectional transmission between the DC bus and an energy storage component is realized by the isolation type bidirectional full bridge DC/DC converter. The purpose of bidirectional flow of energy between the energy storage component and the grid is realized.