Abstract: Under the background of new power system, China is facing the ‘West to East’ power transmission demand of large-scale renewable energy in the future, so it is necessary to plan the corresponding transmission modes. Based on the development scale of renewable energy in the west China after 2030, the installed capacities and geographical distribution of various types of power sources are determined, and the backbone structure of the ‘West to East’ transmission grid and road map are proposed, integrating the long-term sending end DC grids in western China and receiving end UVAC/UHVAC grids in central/eastern China. In order to meet the basic requirements of the new power system, such as safety, controllability, flexibility and efficiency, three VSC-HVDC based DC grid modes are constructed to realize the complementarity of multi-sources in western China and ensure the reliable supply of electric power. The quantity of main primary equipment under three modes is analyzed, and the overall reliability index of the sending end DC grids in western China is calculated. The three modes are comprehensively evaluated in terms of the quantity of equipment and the overall reliability index of the DC grids to determine the priority mode. Finally, referring to the Zhangbei flexible DC grid project, the technical and economic aspects of the optimal mode are analyzed to further verify the feasibility of the mode.