Abstract: A large-scale triaxial testing programme on materials of Jishixia Dam is presented by utilizing the 2000 kN static and dynamic triaxial apparatus in Tsinghua University. Firstly the main function and properties of the large-scale triaxial apparatus are expatiated, as well as the test materials and test method. A total of 6 groups of tests are conducted on main and sub rockfill materials of Jishixia Dam to study the stress-strain and volume-strain relation with different dry densities. The influences of porosity on the mechanics and deformation properties of rockfills are discussed. The results about the deformation behavior of rockfills are expected to provide experimental basis for engineering construction.