We investigated the temperature-dependent optical conductivity of BiCuOCh (Ch = Te, Se) in the terahertz (THz) region. The optical conductivity of BiCuOSe increases with the temperature from 297 to 600 K, whereas that of BiCuOTe exhibits a different trend. In the THz frequency range of 0.4-1.6 THz, these materials show a conductivity increase as the frequency increases. The conductivity of BiCuOTe is greater than that of BiCuOSe. These results can be explained by a two-band structure model and the carrier-carrier scattering process. In addition, we fitted the experimental results to the DrudeeSmith model to explain non-Drude like behavior. The dielectric constant of BiCuOTe depends on the frequency rather than on the temperature, whereas that of BiCuOSe depends on the temperature. (C) 2016 Elsevier B.V. All rights reserved.