The present invention discloses a two-dimensional electromagnetic bandgap plane-crossing waveguide period type slow waver structure which comprises a metal electromagnetic bandgap waveguide structure which is arranged with an input port and an output port, the electromagnetic bandgap waveguide structure comprises a cavity which is arranged with a metal partition board, an electronic beam channel and a metal column at the inner part, and the invention is characterized in that the waveguide of the electromagnetic bandgap structure is S-shaped. The invention uses the EBG waveguide structure for realizing the monomode and high coupling impedance operation of the device in large diameter/period ratio. The invention adopts EBG waveguide structure and combines the disk-loaded waveguide to form aslow wave structure, in the same waveband the physical dimension is increased comparing with the original slow wave structure and has better heat radiating character; comparing with the original slowwave structure with same dimension the coupling impedance is evidently increased.