The invention discloses a DC line fault protection method utilizing current converter active injection and traveling-wave coupling. The DC line fault protection method comprises the steps of utilizinga health pole current converter additional control strategy to inject a feature signal into a DC line within an interval after fault pole DC line fault clearing/isolation and before current converterrestarting/reclosing of a DC power transmission system, wherein propagation properties of the feature signal are different when a DC line fault exists and disappears, utilizing the difference to realize fault property determination of the DC fault line, and further controlling a fault pole power transmission system not to restart/reclose a circuit breaker, thereby realizing DC line fault protection. The DC line fault protection method realizes self-adaptive restarting/reclosing of the DC system in an overhead line power transmission occasion, shortens the power outage duration, ensures the safe and reliable operation of the DC system, and has remarkable direct benefits and indirect benefits.