The invention provides an arc suppression coil grounding system single-phase grounding line selection method. The method comprises a step of collecting bus three-phase voltage, bus zero sequence voltage and branch circuit zero sequence current of different times, a step of calculating the fundamental component instantaneous value u'0(t) of the bus zero sequence voltage according to the bus zero sequence voltage, and judging a phase with a fault according to the amplitudes of the bus three-phase voltage of different times and the fundamental component instantaneous value u'0(t), a step of calculating zero sequence current fundamental component instantaneous amplitude values I0M,x of different times and different positions of a branch circuit of a phase with the fault, and calculating the zero sequence current fundamental component instantaneous amplitude values I'0M, x of the branch circuit after the arc suppression coil compensation effect is completed, and judging whether the branch circuit has a grounding fault according to the zero sequence current instantaneous amplitudes before and after arc suppression coil compensation. A line with an arc suppression coil single-phase grounding fault can be accurately selected without the influences of a field and the polarity of a zero sequence current transformer, the accurate of line selection is effectively improved, the group judgment is not needed, and a line selection process is greatly simplified.