The invention discloses a method and a system for setting a medium-voltage distribution network carrier communication card inductance coupler. The method comprises the following steps: based on Faraday electromagnetic induction law, a calculation formula of coupling voltage on a three-phase cable core or a shield layer of a medium-voltage distribution network cable is determined; cmbined with thestructure principle of Card Inductance Coupler, the mutual inductance calculation formula of Rogowski coil is improved and the improved mutual inductance calculation formula is obtained; and the improved mutual inductance formula is substituted into the effective value formula of coupling voltage, and the improved effective value formula of coupling voltage is obtained. According to the improved RMS formula of coupling voltage, the air gap, primary coil turns, magnetic core material and skeleton size of the card inductive coupler are set. The invention provides a method and a system for setting a card-type inductive coupler of carrier communication in a medium-voltage distribution network, which provides a reliable design basis for parameter setting of a card-type inductive coupler in a cable line.