Abstract: In order to investigate the influence law of different clay doping on the physical and mechanical properties of iron tailings sand. This paper takes iron tailing sand from a tailing pond in Zanhuang County,Hebei Province as the research object,and studies the influence of clay admixture on the physical and mechanical properties of iron tailing sand through compaction test,California bearing ratio test and conventional triaxial test with the help of the improvement method of external clay admixture. The results showed that:the maximum dry density of the improved soil increases and then decreases with the increase of clay admixture;The admixture of clay in iron tailings sand can effectively improve the California load bearing ratio of iron tailings sand;When the admixture of clay is near the critical point of filling the pores of iron tailings sand,the improved soil is easier to be compacted and its strength and stiffness indexes have the best overall performance.