A novel plasma curved waveguide filter based on microcavity coupling structure is presented, which consists of two rectangular waveguide and a rectangular resonant cavity. When light passes through the structure, surface plasmon polaritons (SPPs) can be excited. The propagation properties of the SPPs with this structure are investigated by the finite difference time domain (FDTD) method. The results show that, compared with the traditional straight waveguide structure, the single microcavity curved waveguide structure can generate stronger resonant interaction and higher coupling effect for the bilateral coupling effect induced by the structure. The numerical simulation results show that the resonant wavelength of the filter can be adjusted linearly by changing the cavity length of the resonator. In addition, based on the above design idea, a dual microcavity structure is also proposed. The structure consists of a bent waveguide and two resonant cavities at left and right, which can be used to produce dynamically tunable plasma induced transparency by the superposition of two microcavity transmission waves.