In order to provide a seismic design foundation to the Equipment and Instrument installed in the pool which are related to nuclear safety, in connection with the rectangular pool related to nuclear safety, study the change regulation of the response spectrum on the pool wall according to a liquid-structure coupling analysis between the inviscid, irrotational and incompressible ideal fluid and pool wall. The results show that, when considering the liquid-structure coupling, the response spectrum of the pool has a significant enlargement in the normal direction, and the farther away from the intersection of the wall, the more obvious the magnification is. It is necessary that the response spectrum be given in the tangential direction and the normal direction of the pool wall, the response spectrum amplification at the intersection site of the pool wall is not obvious, the instrumentation should be placed as close as possible to the corner parts of the pool.