Terahertz (THz) time-domain spectroscopy (TDS) is attracting more and more attention recently, and has been growing up as a powerful technique for measuring the material parameters. Indium phosphide (InP), which with short carrier average collision time, high band-gap energy and low effective mass, is growing up as one of the best photoconductive materials for emitting and detecting THz waves. An <i>n</i>-type InP of 0.35 Ω•cm was measured with normal transmitted TDS system for the temperature and frequency ranges of 4.2 - 300 K and 0.2 - 4 THz, respectively. THz beam was placed in a closed box purged with dry nitrogen gas, and the sample was mounted in a MicrostatHe cryostat made by Oxford Instruments. Temperature dependence of THz properties for InP as a function of frequency was characterized.