Abstract: Provided are a power supply control system and a control method thereof. The power supply control system includes: a transformer connected to a power grid; an output socket connected to the transformer via an alternating current bus and configured to be connected to an electric device in the electric vehicle charging station; and an energy storage system including an AC/DC bidirectional converter and an energy storage battery connected to the alternating current bus via the AC/DC bidirectional converter. The energy storage system is configured to be controlled to, in response to the power supply control system being in an uninterruptible power supply mode: switch the AC/DC bidirectional converter into an inversion state; and output no electric energy when the power grid has a normal voltage and supply electric energy only by the energy storage system when the power grid has an abnormal voltage.