Abstract: The natural vibration and mobility of stiffened laminated composite plate were investigated with the finite element method. Based on the first-order shear deformation theory for laminated composite plate, Mindlin shell elements with four nodes were utilized to obtain a discrete structure. Also the finite element dynamic equations of structure were formulated, and computer code was developed. The facts that the driving-point mobility and transfer-point mobility of the structure varies with the change of factors, e.g. stiffened plate＇s damping, exciting position, boundary condition and the number of the stiffened beams, were discussed. The calculation results could be used as a basis for further research of efficiency of power transfer and vibration isolation. A method for optimum design of vibration and acoustics could be obtained.