A novel Metal-Insulator-Metal (MIM) structure filter was constructed by using the boundary-coupled method. The structure consists of a convex ring resonator and a waveguide. The magnetic field distribution, transmission spectra and resonance wavelength distribution of the convex ring cavity waveguide structure were obtained by Finite Element Method (FEM) numerical simulation. The influence of various structural parameters on the transmission characteristics of the filter is analyzed in detail.The results show that the proposed convex ring filter has narrow transmission peaks, smooth transmission spectra and other characteristics, and the minimum stopband transmission rate can reach 0.001, and the passband transmittance can reach 0.977. When the structural parameter h2 and neffis increased, the corresponding transmission spectrum undergoes a significant red shift. When the structural parameter L1 is increased, the transmission spectrum hardly changes. By adjusting and optimizing various structural parameters of the structure, the resonance wavelengths can distribute in the vicinity of 850 nm (the first communication window) and 1 550 nm (the third communication window), and can be well used in communications.