The three-dimensional turbulent flow fields of missile Vertical launching system(VLS) are computed.Cell-centered finite-volume method and 3rd-order upwind spatial differencing with TVD option is applied for Navier-Stokes governing equations.Dual-time stepping and preconditioning procedure are utilized for improving the calculating convergence velocity. The diagonalized

dual-time ADI algorithm is employed to integrate the governing equations.Shock forming in the plenum chamber is simulated accurately.The complex flow pattern in Vertical Launching System was described veritably.The current studies show that the pressure of jet center at the bottom of plenum chamber oscillates with a frequency about 1200Hz.