Abstract: A new combined test apparatus is developed on torsion vibration principle, which can be used to measure shear-wave velocity and to determine cyclic liquefaction resistance of soil specimen simultaneously. The relation between the shear wave velocity and the cyclic liquefaction resistance is analyzed for a lot of undisturbed and remolded specimens of same kind of sand with same consolidation pressure, which are taken from more than 20 sites within the depth of 20 m under ground surface. The results show that the relation is good if the strain criterion for evaluating liquefaction is not larger than 6%.