A single-stage three-phase power supply conversion device includes a three-phase rectification and commutation module and a DC/DC conversion module; the three-phase rectification and commutation module has a three-phase AC connection end, a DC source first connection end, a DC source second connection end and a DC source third connection end, and the DC/DC conversion module has a first connection end. a second connection end, a third connection end, a DC source positive connection end and a DC source negative connection end; a three-phase AC source is connected to the three-phase AC connection end of the three-phase rectification and commutation module, the DC source first connection end of the three-phase rectification and commutation module is connected to the first connection end of the DC/DC conversion module, the DC source second connection end is connected to the second connection end of the DC/DC conversion module.