Abstract: A fluid-structure coupled finite element model is established which consists of Lagrange element for simulating mast structure and correlative decks. Euler element for simulating air around and inside the mast. Multiple Euler domains are used to simulate the air interaction in and out of the structure. Mast and air are coupled with general coupling method. The model is calculated by MSC/DYTRAN where the Euler equations are solved with second-order Roe solver, and MSC/PATRAN is used for pre-processing and post-processing. Then the deformation and rupture of mast structure under air explosion is simulated. When the mast is in rupture, the air pressures inside the mast are changed arising from the shock wave propagation. Numerical simulation shows that the effect of strain rate on the dynamic response should be taken into account during the material nonlinear phase.