Abstract: Compared with plastic concrete and normal concrete, the polymer diaphragm wall has the characteristics of light weight, early strength, environmental conservation and durability. During its construction, it has speedy, economic, and practical characteristics and few influences on the dam. The polymer diaphragm wall has been successfully used in earth-rock dams. But at present the static and dynamic characteristics of earth-rock dams are seldom studied. The Duncan-Chang E-B nonlinear model is used and the contact element is set up between the diaphragm wall and the dam for the FEM model. A comparison of stresses on the diaphragm wall among polymer, plastic concrete and normal concrete under static and seismic loads shows that the stress on the polymer diaphragm wall is the least and it is not easy to be failed. The polymer diaphragm wall for earth-rock dams has preferable security.