We demonstrate terahertz (THz) imaging and spectroscopy of single-layer graphene deposited on an intrinsic Si substrate using THz time-domain spectroscopy. A singlecycle THz pulse undergoes multiple internal reflections within the Si substrate, and the THz absorption by the graphene layer accumulates through the multiple interactions with the graphene/Si interface.We exploit the large absorption of the multiply reflected THz pulses to acquire high-contrast THz images of graphene. We obtain local sheet conductivity of the graphene layer analyzing the transmission data with thin-film Fresnel formula based on the Drude model. © Springer Science+Business Media, LLC 2012.