For the improved pseudo 3D FSI model of large span beam aqueduct put forward by the first author of this article，research on the 3D seismic simulation effects of the model. Results showe that the simplifed FSI model reflects not only the good 3D seismic fsi effects, but also can significantly reduce the computing costs, greatly improving the computational efficiency. Therefore, the pesudo 3D FSI model can be used as a practical calculation method for multi-span joint 3D FSI seismic analysis of large-scale aqueduct.