The invention discloses a method and a system for locating a single-phase earth fault of a parallel damping turn-adjustable type arc-extinction coil. The method comprises the following steps: controlling the short-term trigger conduction of an anti-parallel thyristor by using a microprocessor, thereby generating a disturbing signal which includes a disturbing voltage signal and a disturbing current signal; extracting the disturbing signal at an outlet end of a fault circuit; performing Fourier transform analysis on the extracted disturbing signal; acquiring equivalent impedance data under different frequencies of the single-phase earth fault of the parallel damping turn-adjustable type arc-extinction coil according to a linear relation of the disturbing voltage and the disturbing current in a frequency domain; constructing an equation set by utilizing the equivalent impedance data under different frequencies and an equivalent impedance expression of the single-phase earth fault of the parallel damping turn-adjustable type arc-extinction coil; solving the equation set, thereby acquiring a fault distance.