Abstract: Aqueduct is a kind of thin-walled bar structures. Based on the theory of Volasov and Housner, a seismic response analysis model of thin-walled space aqueduct with fluid-structure coupling is established in this paper. In this model, transverse deformation, vertical deformation, longitudinal deformation, free torsion deformation, constrained torsion deformation and fluid-structure coupling between aqueduct and water body are all taken into consideration. The element stiffness matrix and the mass matrix of the thin-walled beam portion of aqueduct are derived by energy principle and the transverse seismic response equations are established without water or with design level water in aqueduct, respectively. Using the model, the seismic time-history responses of a single-pier aqueduct are calculated, and the model is verified through the comparison with analytical solution. Moreover, it is found that the seismic responses are different in the two cases of no water and design level water. The model is shown to be simple and practical for aqueduct's seismic response analysis with fluid-structure coupling.