Abstract: In the circumstance of underwater explosion, ship equipments dynamic response characteristics are key factor affecting the working capability and reliability. Numerical simulation is done for the research of time domain dynamic structural response of large-scale ship equipments and ship structure on the condition of underwater explosion. The conclusion indicates that integrate analysis result coincides with that from experiments. Meanwhile, integrate analysis is used to determine the characteristic ship cabin structure element length, not only to reduce the amount of calculation but also for good precision.