Severe liquefaction damage was caused to reclaimed land in coastal areas during the 2011 Great East Japan Earthquake. The ground level has sunk and many houses have tilted so badly on reclaimed land in bay areas around Tokyo such as Urayasu, Funabashi, Yokohama, etc. The phenomenon is often occurred in saturated loose sandy soils which are more vulnerable to liquefaction damage. If it is possible to classify soils by means of ground investigation, risks of liquefaction could be predictable. This paper proposes the Screw Driver Sounding test as an accurate soil classification method. The effectiveness of the assessment method was confirmed through some case studies on site investigation.