A new kind of refractive index sensor based on a hollow optical fiber with a metal-dielectric-metal multilayered films structure is proposed and its transmission spectrum is calculated by the establishment of an optical model. The performances are analyzed for the designed sensors with SiO2, cycloolefine polymer and AgI as the dielectric materials, respectively. When the refractive index of the detected liquid in the hollow optical fiber is in different ranges, the principles of the guided mode resonance, surface plasmon resonance (SPR) and waveguide-coupled SPR are employed for sensing by the designed sensor, respectively. Compared with the traditional hollow fiber sensors, the proposed sensor not only has a greatly extended detection range which is 1.3-1.64 and almost covers all the refractive indexes of liquids, but also its figure of merit is increased up to twice.