Properties of people have received terrible damage from liquefaction during large scale earthquakes in Japan. In this study, a new suspension grouting material which composed of fine silica particles and fine calcium hydroxide was developed for soil improvement and the effect on liquefaction countermeasure of the grout was investigated. In order to investigate dynamic behavior of structures on liquefiable sand and improved sand centrifuge modeling test was performed. From these results of experiments, it was confirmed that unim-proved sand liquefied in each shaking event. On the other hand, decreasing of stiffness and area on hysteresis loop were not confirmed in the improved sand. Additionally, settlement in the improved sand was smaller than that in the liquefiable sand.