The cavity ring-down method has an extremely high measurement sensitivity to the absorption of a medium in the cavity and can be used to accurately measure cavity loss. Based on the theories of free carrier absorption and resonant cavity, this study establishes a theoretical model of an optical cavity ring-down to measure the properties of semiconductor materials and derives the functional relationship among the cavity ring-down signal, semiconductor material characteristic parameters, and cavity structure parameters. Simulation analysis and experimental verification are performed. Simulation results show that the cavity ring-down method can be used to accurately measure semiconductor material properties, such as doping concentration and resistivity. Meanwhile, based on the proposed method, the doping concentration and resistivity of a crystalline silicon wafer are determined experimentally to be (2.65±0.38)×1016cm-3 and (0.61±0.07)Ω?cm respectively, exhibiting the high application potential of this method for measuring semiconductor material properties.