Abstract: Long-span arch shell steel dome is a new type roof structure which is composed of stiffening rib arches, lightweight shell material, and a seat ring used to connect the steel roof with the supporting members. The structural simulation was conducted by using ansys software. Under the earthquake excitation, the seismic responses of the long-span arch shell steel dome were obtained, including the internal forces, stress and displacements. The analysis results show that long-span arch shell steel dome has better stability under the excitation of strong earthquakes.