A series of reverse-impact experiments is performed on vanadium at peak shock pressures from 32 GPa to 88 GPa. A displacement interferometer is used to measure the particle velocity profile at the vanadium/LiF window interface. Analysis of these profile provides a measure of sound velocity of vanadium in the Hugoniot state. The transition from body-centered cubic structure to rhombohedral structure phase at ～ 60 GPa is identified by the discontinuity of the sound velocity against shock pressure. This transition pressure is consistent with the data from high pressure diamond anvil cell experiments and first-principle calculations.