Many faults of single core cables are related to metal sheath. The simplified model that only considers the core cannot realize the sheath-related fault location. This paper proposes a novel fault location method considering the metal sheath of the cable basing on the distributed parameter model. First, based on the distribution parameter theory, the equivalent distribution parameter circuit of the fault cable of considering the metal sheath is analyzed, the voltage and current equations are established; then, the unknown parameters in the voltage and current equations are solved through boundary conditions, the voltage and the current value of both sides of the fault point are obtained; finally, the fault distance is obtained by iterative search of the ranging equation. The proposed method transforms the complex phase network into mutually independent sequence network, which makes the algorithm simple and effective. A large number of simulation results show that this algorithm can achieve the accurate distance measurement of sheath-related faults (sheath-to-ground faults, core-sheath faults, and core-sheath-to-ground faults), and the ranging error is within 1.5%. The results are not affected by the fault location, fault type and the transition resistance.