Abstract: A measurement scheme carried out in a tank is designed to obtain the compressionaland shear-wave velocity of large elastic material. A hydrophone is used to receive the high frequency acoustic signals which penetrate the tested material, in order to determine the transmission time from source to hydrophone, the transmission time is also calculated according to the ray acoustic theory in layered media. A cost function is built based on the measured and the calculated transmission time, then the compressionaland shear-wave velocity can be obtained using the optimization algorithm. Compared with traditional measurement scheme, this approach can not only get the 2 kinds of sound velocity in tested material at the same time, but also keep the integrality of the tested material. With the proposed measurement system, the uncertainty of measurement result is less than 3.5%.