Abstract: Finite element model of a broadleaf-tree swaying in the wind is established in the paper.Effects of fluid-structure interaction between wind and the tree are studied by discussion of the two vibration modes：the average wind pressure mode and the vortex induced vibration mode.A method called “virtual material method” is proposed to accelerate the finite element simulation.The swaying of a tree under different wind scale can be simulated and the resultant motion is in accordance with the wind scale table.Animations of trees swaying in the wind can be generated through the simulation resultant database.