In this work, an undoped Ⅲ-Ⅴ group InSb crystal was prepared through a Horizontal Bridgman method. The as-grown crystal has standard F43 m phase structure and precise stoichiometric ratio at room temperature. Its electrical and thermal transport properties along (110) cleavage plane has been investigated. The electrical conductivity σ is increased from 1224.6 Scm⁻¹ to 2282 Scm⁻¹ in the temperature range of 300−700 K. The Seebeck coefficient S is always negative, which means this crystal is a n type semiconductor, and the largest S is −180.2 μVK^-1 near 700 K. As for the total thermal conductivity k_tot, the lowest value of 8.2 Wm^-1 K^-1 is achieved under the same temperature. Ultimately, a maximum figure of merit ZT = 0.63 is obtained around 700 K which reveals InSb crystal might be a promising middle- temperature thermoelectric (TE) material for energy conversion application in the future.