Abstract: Distributed capacitive current affects the performance of DC line pilot protection. In this paper, the fault characteristics of the ratio of differential current to distributed capacitive current are discussed and analyzed on three-terminal hybrid high-voltage DC transmission line. Since both differential current and distributed capacitive current decrease with the increase of transition resistance, the ratio of differential current to distributed capacitive current is used as the criterion to weaken the influence of transition resistance on the criterion and improve the sensitivity of protection. On this basis, a pilot protection method based on the ratio of differential current to distributed capacitive current is proposed. Simulation verification based on PSCAD/EMTDC shows that the proposed protection criterion is simple to set and naturally has the function of fault pole selection, can reliably identify the internal and external faults, has strong resistance to transition resistance, and has high sensitivity and reliability.