The carrier transport mechanism of layered molybdenum disulfide (MoS₂) is studied by terahertz time-domain spectroscopy. The sheet conductivity and the change of sheet conductivity of layered MoS₂ under different pump excitations is studied. The carrier mobility is obtained by analyzing the optical conductivity with the Drude and Drude–Smith models. The carrier dynamics of layered MoS₂ is investigated by an optical pump-terahertz probe. It was found that multilayer MoS₂ exhibits a higher optical conductivity and mobility than monolayer MoS₂, especially under pump excitation.