Seismic analysis of nuclear polar cranes is a core verification method to ensure their functional integrity under safe shutdown earthquake (SSE) conditions. To address the massive computational challenges brought by multiple geological conditions and different holding positions, a dynamic simulation of nuclear polar cranes is conducted considering nonlinear factors. Then the multi-point excitation time history analysis is completed by inputting SA/MA/HA site displacement time history data, and the stresses of key components are compared to deeply explore the influence of three geological conditions on seismic performance. The study reveals that the peak responses occurred in different geological conditions and there is not a certain condition envelops all dangerous results. So, it is suggested that corresponding analyses should be conducted depending on the actual different site conditions. It is not feasible to adopt a single scenario as the overall reference. Only in this way can the analysis results be more reliable.