The invention discloses a calculation method for the grounding induction current of a single-point metallic fault of a cable sheath. The method comprises the steps of: S1, calculating and measuring the resistance R and the reactance X of the metal sheath of a cable, the grounding resistance R1 and R2 at the two ends of the cable, and the earth leakage resistance Re; S2, determining division proportion factors alpha1 and alpha2, and measuring the grounding resistance Rf at the position of a fault; S3, calculating induced electromotive forces U1, U2, Uf1 and Uf2 generated by the current flowingthrough the cable core of a three-phase cable, and calculating induced electromotive forces U1', U2', Uf1' and Uf2' generated by the loop current flowing through the cable sheath of the three-phase cable; S4, calculating the loop currents I1, I2, If1 and If2 of the cable sheath. According to the invention, the calculation method for the grounding induction current of the single-point metallic fault of the cable sheath is practicable and feasible. By means of the method, the value of the induced current of the cable, at any position and any phase and in the single-point fault condition, can beconveniently calculated.