Abstract: The response of fuel-tank-sioshing to aircraft maneuver is a difficult mathematical problem to he solved. Beginning with setting up the mechanical mode; and the respective mathematical model, this paper uses both F. E. and B. E. M. to imitate the sloshing process. The paper has developed some special techniques to deal with strong nonlinear characteristics, and provide satisfactory numerical results of displacements and stress for low frequency, resonance, high frequency and fuel tank dynamic response characteristics. The program not only assures convergence and stability of the solution but also has the function of graphic display. It is a valuable technique to deal with the strong nonltear oscillation of fuel tank with large amplitude and moving boundary condition on free surfaces

Key words: boundary element method (B, E, M, ), free moving boundary solshing, response