The invention is applicable to the technical field of power distribution networks and provides a tuning method, a terminal device and a system for an arc suppression wire coil of a power distributionnetwork. The method comprises the following steps: a neutral point voltage of the power distribution network is obtained; when the neutral point voltage is greater than a preset threshold value, a capacitance current of the power distribution network is determined; a target number of wire coil turns of the arc suppression wire coil is determined according to the neutral point voltage and the capacitance current, the number of turns of the arc suppression wire coil is adjusted to be the target number of coil turns. The tuning method, the terminal device and the system provided in present invention can help improve tuning accuracy.