Abstract: In order to investigate the immobilization efficiency of heavy metals in soil by functionalized sepiolite materials, the leaching effect of different materials, sepiolite (SEP), sepiolite-diethyldithiocarbamate (SEP-DDTC), sepiolite-3-mercaptopropyltriethoxysilane (SEP-MPTES) on soil polluted by Cd were measured by soil column simulated acid rain leaching. The results show that the pH values of soil increased by 0.80~0. 99 after the leaching of simulated acid rain with pH 4.0, and the pH values of leaching also increased obviously. When the acid rain pH value was 4.0, compared with the CK treatment, the SEP treatment and SEP-MPTES treatment had significant increases in accumulation leaching amount of Cd by 66.45% and 11.49%, respectively. However, the SEP-DDTC treatment had a significant decrease in accumulation leaching amount of Cd by 45.98%. Compared with three layers of soil available cadmium content after simulated acid rain, SEP-DDTC treatment and SEP-MPTES treatment were lower than CK, SEP-DDTC treatment was 0.054 mg·kg^-1 lower than SEP-MPTES treatment in average. It indicates that SEP-DDTC is a potential material for soil heavy metal Cd remediation.