Abstract: Abstract: The lightweight soils mixed with rubber chips of scrap tires are concocted from soils, rubber chips of scrap tires, cement and water by appropriate proportions. They are usually used in many engineering practices such as roadbed fills, pipeline backfills and subgrade fills. So it is important to study the deformation characteristics of RST lightweight soils under dynamic loads. Firstly, the physical properties of the ingredient materials in RST lightweight soils are studied. Then, the sample mixture ratio and loading scheme are designed. Finally, the effects of confining pressure, rubber chip content and cement content on the dynamic deformation characteristics of RST lightweight soils are studied through laboratory dynamic triaxial tests. It is shown from the experimental results that the dynamic stress-strain curve of the RST lightweight soils is in a hyperbolic form, and their dynamic strain decreases with the increase of the confining pressure and the cement content under the same dynamic stress. In addition, the dynamic elastic modulus E_d of the RST lightweight soils increases with the increase of the confining pressure and cement content under the same dynamic strain, decreased with the increase of the rubber chips, and the curve tends to be smooth when the content of rubber chips increases.