We design and numerically investigate a high-quality (Q)-factor, high modulation depth, and multiple Fano resonances in an all-dielectric metamaterial consisting of an asymmetric nanocylinder dimer. It is demonstrated that, due to excitation of subradiant modes, eight sharp Fano resonances are achieved by removing parts of the nanocylinder from the edge, and the corresponding Q-factors and modulation depth are flexibly tuned by geometric parameters. Further, we demonstrate that the maximal figure of merit exceeds 2352 with a RI sensitivity of 400 nm/refractive index unit (RIU), and even the minimal figure of merit exceeds 277 with a RI sensitivity of 120 nm/RIU. The metamaterial shows the potential applications in designing multiple switching, filters, and sensors.