The research aims at exploring the possibility of GW level remote HVDC through a new type of superconducting material (MgB₂) as a cost-effective and environmental-friendly DC line and liquid hydrogen as coolant. The necessity and advantages of superconducting DC transmission are analyzed firstly. Then basic method of HVDC converter is explained. The MgB₂ superconducting cables and liquid hydrogen refrigeration system are introduced and the DC transmission control strategy based on twelve pulse converter is illustrated. Through the Pscad software, the simulation of superconducting DC transmission is completed and the line power losses between the MgB₂ HTS superconducting cable and traditional cable under the same condition are compared, which proves the advantages of low loss and unlimited capacity and provides the preliminary basis for the development of MgB₂ HTS superconductor in the field of superconducting DC transmission.