The integrity and reliability of nuclear power equipment are directly related to nuclear safety. According to ASME safety classification standard, the supports of pressure vessel, main pump and main cooler in reactor coolant system belong to nuclear safety class I and seismic class I. In order to verify the safety of the supports, according to the relevant regulations, it is necessary to carry out seismic analysis. The response spectrum method is based on the modal results, which can more accurately reflect the dynamic characteristics of the structure, so it is widely used in nuclear power engineering. Response spectrum method includes single point response spectrum method and multi-point response spectrum method. The single point response spectrum method uses the same seismic spectrum as the calculation input, which is suitable for the equipment with single support and small span; while the multipoint response spectrum method inputs different seismic spectra at different constraint points, which is suitable for equipment with multiple supports and large span. In this paper, the above two methods are used to carry out the seismic analysis of the main equipment support of the reactor coolant system, and the application of different seismic analysis methods in nuclear power equipment is studied.