Multi-terminal mode of the receiving ends of HVDC transmission technologies might be helpful for solving the stability problems caused by large HVDC infeed or especially multi-infeed HVDC. This paper introduces the design characteristics of two modes of multi-terminal HVDC: two poles connected to two different AC grids (TPTDG), and parallel type multi-terminals HVDC (MTHVDC). Some results of AC and DC fault simulation analysis by EMTDC are presented. By comparing the two modes’ properties under faults and influences on control protection system and AC grids, some different characteristics are obtained. It is pointed out that the capability of stable operation of HVDC might be affected with any pole of TPTDG connected to weak AC system, and the inverter station will be substatially less affected with transient faults occurred to the other DC line. The different characteristics between the two modes will provide reference for design optimization of large HVDC access.