The invention relates to a mistaken-opening-preventing and locking device and method for switch cabinet isolation baffles. According to the technical scheme, the device comprises a cabinet body, and the cabinet body is provided with the two isolation baffles; the two isolation baffles are provided with a first fixing sheet and a second fixing sheet respectively, the first fixing sheet and the second fixing sheet are connected through two locking sheets, the first fixing sheet and the second fixing sheet both form an L-shaped structure through two face plates, and the first fixing sheet and the second fixing sheet are each provided with a first through hole and a second through hole; each locking sheet is of a rectangular structure and is provided with three through holes, two through holes in each locking sheet serve as mounting holes, and one through hole in each locking sheet serves as a lock hole; the first fixing sheet and the second fixing sheet are connected with the locking sheets respectively, the two locking sheets are connected through the lock hole, and the lock hole is locked through an electromagnetic lock. The mistaken-opening-preventing and locking device and method for the switch cabinet isolation baffles have the advantages that the fixing sheets and the locking sheets are simple in structure, cost is low and mounting is convenient.