This study designed a ring resonator based on a 2×2 fiber coupler to create a high-performance microwave photonic filter with tunable broadband, single transmission peak, and narrow filter bandwidth. The output characteristics of the resonator were deduced, simulated, and measured. The high-performance microwave photonic filter was realized by combination with an ordinary optical filter. The experimental results show that the filter bandwidth of the designed fiber ring resonator can be as low as 1.2 MHz. It can realize a dynamic selection of any single transmission peak after cascading with the common tunable optical filter. The optical RF signal can be tuned to 40 GHz through a coherent detection link. Compared to that with a traditional noncavity microwave photonic filter, the proposed resonator significantly reduces the filter bandwidth. Meanwhile, compared to the single-fiber ring resonator, the proposed resonator can realize a dynamic selection of any single transmission peak. The designed fiber ring resonator is expected to be used in ultra-fine spectral analysis and optical fiber sensing in the future.