A full DC boost-buck power transmission system, comprising: at least one boost station; at least one buck station; a power grid management center; a DC power supply; and a cable provided for connecting the at least one boost station to the at least one buck station; characterized in that the at least one boost station comprises a plurality of first battery packs, and the first battery packs are connected in parallel for storage of DC power from the DC power supply; when the storage of the first battery packs is completed, the first battery packs are disconnected from the DC power supply and are connected in series to perform the boost operation, and then connected to the cable to supply the DC power to the at least one buck station; and after transmission of the DC power is completed, the first battery packs are disconnected from the cable and connected in parallel, and then connected to the DC power supply for the storage of the DC power; the at least one buck station comprises a plurality of second battery packs, and the second battery packs are connected in series for transmission of DC power from the boost station to the buck station; when the transmission of the DC power is completed, the second battery packs of the at least one buck station are configured to form a plurality of single battery pack subunits, a plurality of series subunits and a plurality of parallel subunits, so that the different kinds of the subunits are independently connected to their corresponding loads for transmission of the DC power from the subunits to their corresponding loads; after the supply of DC power from the subunits to their corresponding loads is completed, the second battery packs in the at least one buck station are disconnected from the loads and connected in series, and then connected to the cable for transmission of DC power from the boost station; and the power grid management center is configured to switch connection modes of the battery packs (XDCZ00) in the at least one boost station and the at least one buck station between series connection and parallel connection and to switch connection and disconnection of at least one booster station with the cable as well as to switch connection and disconnection of at least one buck station with the cable, to achieve storage, boost, transmission, buck and supply of DC power. at least one boost station; at least one buck station; a power grid management center; a DC power supply; and a cable provided for connecting the at least one boost station to the at least one buck station; characterized in that the at least one boost station comprises a plurality of first battery packs, and the first battery packs are connected in parallel for storage of DC power from the DC power supply; when the storage of the first battery packs is completed, the first battery packs are disconnected from the DC power supply and are connected in series to perform the boost operation, and then connected to the cable to supply the DC power to the at least one buck station; and after transmission of the DC power is completed, the first battery packs are disconnected from the cable and connected in parallel, and then connected to the DC power supply for the storage of the DC power; the at least one buck station comprises a plurality of second battery packs, and the second battery packs are connected in series for transmission of DC power from the boost station to the buck station; when the transmission of the DC power is completed, the second battery packs of the at least one buck station are configured to form a plurality of single battery pack subunits, a plurality of series subunits and a plurality of parallel subunits, so that the different kinds of the subunits are independently connected to their corresponding loads for transmission of the DC power from the subunits to their corresponding loads; after the supply of DC power from the subunits to their corresponding loads is completed, the second battery packs in the at least one buck station are disconnected from the loads and connected in series, and then connected to the cable for transmission of DC power from the boost station; and the power grid management center is configured to switch connection modes of the battery packs (XDCZ00) in the at least one boost station and the at least one buck station between series connection and parallel connection and to switch connection and disconnection of at least one booster station with the cable as well as to switch connection and disconnection of at least one buck station with the cable, to achieve storage, boost, transmission, buck and supply of DC power.