Terahertz sensing is one of the most promising methods for label free and noninvasive detection of refractive index changes. However, the figure of merit (FOM) of terahertz sensor has been low due to the low radiation and absorption loss of terahertz wave. In this paper, a metamaterial sensor based on gold and silicon dioxide is proposed. The structure not only realizes narrow-band absorption with five absorption peaks, but also improves FOM to 1792. These excellent performances are based on the classical magnetic resonance and Mie resonance, which provide a platform for the design of multi-band photodetectors and high sensitivity sensors.