To narrow the single-channel bandwidth of the comb filter and increase the utilization rate of limited frequency band resources,a surface plasmon polaritons (SPPs) interference comb filter was proposed in this paper.A significant increase in pass band transmittance ,narrowing of the single-channel bandwidth and channel numbers was achieved by this filter.To explore the physical mechanism and optimize the filter structure,the effect of the structural parameters of the comb filter on the transmission spectrum was numerically simulated by finite difference time domain (FDTD) method.Experiment result shows that the single-channel ultra-narrow bandwidth of the comb transmission spectra results from dual interference of SPPs and graphene microcavity.As a result,the comb transmission spectra are mainly concentrated in the near-infrared bands (1—1.24 μm).By optimizing the structure parameters,the single-channel bandwidth can reach 4.2 nm,and the number of channels is 18.Additionally,the adjacent channel spacing,single-channel bandwidth and channel numbers can be selected by adjusting the width of the silica top layer.Particularly the comb channel is excited by its material coupling resonance in the filter,which means that it is simple and more suitable for on-chip integration.