Abstract: Based on modal analysis theory, the rectangle storage box and beam element have been established, the stress strength under the state of no-load and full-load and vibrate modal below the sixth order have been analyzed. The results indicate that the reactions of support under hydrostatic pressure are 8 285.4 N and 1 222.9 N respectively with full-load and no-load, the maximum stress strength of whole box appears in the joint between the bottom of lateral plate and long support of base plate, and the maximum displacements of the box in x, y, z direction are less than 3.5 mm, which can be accepted in the aspect of practical engineering. Each modal frequency is not a resonance frequency for the integral structure, and the vibration mode and amplitude are within a controllable and acceptable range, which can satisfy the demands of reliability and safety for military equipment. By analyzing technical parameters of 316L, Q235 and aluminum which are used to make rectangle storage box, the technological advantage of Q235 and aluminum in enhancing the overall performance of military equipment, lightweight and reliability design have been defined.