Based on the traveling wave theory, the distributed parameters equivalent model of 27. 5 kV cable was built and verified by simulating the speed of lightning wave in different segments. Make sure the necessity of the fitted protector on metal sheath and the reasonableness of protection provided in the first end by theoretical calculations. On this basis, when the lighting current intruded upon the cable core along the catenary, one software was adopted to simulate and study the influence of the cable length, grounding resistance of the metal end and impedance of the core end on the lighting induced voltage of cable metal sheath. The results show that the average of the maximum value of sheath lightning induced voltage may be the smallest when the cable length is 800 m; when the grounding resistance value is in the range of 2. 5~ 3 Ω, the average of the maximum value of sheath lightning induced voltage may be the smallest, and they are lower than 25 kV, if the grounding resistance value is more than 5 Ω, the maximum value of sheath lightning induced voltage may exceed the lightning impulse withstanding voltage of outer sheath, leading to the breakdown of outer sheath; when the cable end is connected to a short circuit or a larger capacitive impedance, the sheath lightning induced voltage may be very large and may go far beyond the lightning impulse withstanding voltage of outer sheath, while the cable end is connected to an open circuit or an inductive impedance, the sheath lightning induced voltage may be smaller.