Abstract: To investigate the effect of moisture content on the density and strength of sand EPS beads mixed lightweight soil,5 mix proportions are defined based on uniform experimental design method considering the two factors,cement content and EPS beads content,at 5 design levels.Laboratory density tests and uniaxial compression tests are conducted on sand EPS beads mixed lightweight soil.To determine the optimum moisture content of sand EPS beads mixed lightweight soil,the specific strength is imported.The binary search method is used to determine the optimum moisture content of the 5 mix proportions.The results show that the increase of moisture content is beneficial to the effect compaction,and the specific strength method is satisfactory for the determination of the optimum moisture content.The optimum moisture content is affected by cement content and EPS beads content.