Abstract: Aiming at the problems existing in the line protection of the existing LCC-MMC multi-terminal hybrid DC system, a single-end protection scheme for multi-terminal hybrid DC lines based on the initial current traveling wave phase is proposed. Firstly, based on the fault conditions of different locations and types of multi-terminal hybrid DC transmission lines, the analytical formula of the traveling wave of the incident voltage of the DC line is derived and its high-frequency phase is calculated. Secondly, based on the principle of traveling wave refraction and reflection at the line boundary and the measured wave impedance characteristics, a criterion for identifying inside and outside the zone using the phase of the initial current traveling wave is proposed. In addition, the lightning strike interference criterion is constructed based on the phase characteristics of the incident traveling wave in the low-frequency band of lightning strikes and short-circuit faults. Finally, a Kunliulong multi-terminal hybrid DC system model is built in PSCAD/EMTDC for simulation verification. The results show that the proposed protection can meet the fault judgment and line selection requirements only by using single-ended quantity information, and has a certain anti-transition resistance capability (500 Ω) while meeting the speed requirement.