The invention discloses a filtering system used for a power grid. The system comprises a plurality of filtering devices arranged on a three-phase transmission line; a detection device connected with the three-phase transmission line and also respectively connected with the plurality of filtering devices, wherein the detection device is used for detecting a current signal of the three-phase transmission line, and switching the running statuses of the filtering devices according to a received control instruction, wherein the running statuses comprise commissioning and decommissioning; and a mobile terminal in wireless connection with the detection device, and is used for determining whether to transmit the control instruction based on the current signal transmitted by the detection device. The filtering system used for the power grid provided by the invention solves the technical problem in the relevant technology that the effect of using filtering equipment to filter is poor.