The present invention discloses a slow wave structure suitable for a dual-sheet backward wave oscillator. The structure comprises a rectangular waveguide and a plurality of vertical metal panel pair structures, each vertical metal panel pair structure comprises a pair of vertical rectangular metal panels, one rectangular metal frame and a pair of metal strips, the upper and lower half portions ofthe vertical rectangular metal panels are respectively provided with rectangular holes, the two vertical rectangular metal panels are arranged at the internal portions of the rectangular metal framesin parallel, and the two metal strips are configured to respectively connect with vertical rectangular metal panels and the rectangular metal frames; and the rectangular metal frames in the vertical metal panel pair structures are connected in order to take as an integration inserted into the rectangular waveguide to form a slow wave structure. The slow wave structure suitable for a dual-sheet backward wave oscillator is high in output power and electron efficiency.