Abstract: Nowadays seismic response analysis for most of suspen-dome structures is assumed their foundations constrained by rigid boundary conditions． However，the soil around the foundation may be deformed when the soil excited by the earthquake wave． In order to clarify the real seismic performance of a suspen-dome structure under earthquake excitation，a soil-structure interaction ( SSI ) model of suspen dome structure with 92 m span was established，which was simulated by S-Ｒ model． The natural dynamic characteristics and seismic response of the structure were analyzed． The results showed that the nature frequency of the suspen-dome structure decreases significantly considering SSI． The maximum compressive stress of the members and the maximum displacement of the joints of the upper-shell of suspen-dome structure increased sharply while the maximum stress of struts，steel tie rods and cables decreased to some extent．