Abstract: Expanded polystyrene treated lightweight soil is a new geotechnical material with light-density,high-strength,environment-efficacy and low-price,but there wasn’t any construction experience with it in China before.It was used in road of 88⁷0 entrance in Xin′anjiang hydroelectric power plant.Based on this project,its construction technology was summarized.It was proved that the effect of decreainglection time and improving safety could be achieved.