The invention discloses an SF6 leakage warning device for a distribution network switching station. The distribution network switching station at least comprises line inlet switches and line outlet switches, wherein a secondary chamber is arranged on the side of the distribution network switching station, the line outlet switches are mounted in switch chambers filled with SF6 gas, and piezoresistors of which the resistance values can be decreased with the leakage of the SF6 gas are also mounted in the switch chambers; a loop is formed by the piezoresistors and a terminal strip placed in the secondary chamber of the switching station, the terminal strip is connected with a trigger switch controller, and a normally open switch matched with the trigger switch controller and the warning device are connected in series so as to constitute a warning loop. The SF6 leakage warning device has the characteristics of simple structure and convenience and reliability in use, sensitive on-off action is ensured, and the safe operation of the power grid is guaranteed.