In this study, a nano-circular resonant cavity filter embedded with a symmetrical sector metal block based on metal-insulator-metal (MIM) is developed using the finite element method. It is found that by changing parameters such as the sector resonance angle, circular resonant cavity radius, coupling distance, and refractive index of medium in the resonant cavity, one can effectively adjust the transmissivity characteristics of the proposed structure. The filter shows two significant resonance peaks with the transmissivity up to 76% and quality factor to 40, which is suitable for efficiently achieving a tunable dual-channel bandpass filter. The parameters of the proposed structure are adjusted and optimized to enable the corresponding resonant wavelengths distributed in the 850 nm and 1310 nm optical communication windows of near-infrared band optical fiber communication. This structure provides an important theoretical basis for designing the next-generation high-performance nano-plasmonic filters in the field of optical communication.