Base isolation, as a well-established technology, has been widely applied in many important infrastructure and critical fields. In theory, the advantages of base isolation technology can not only be fully utilized in the seismic safety of nuclear power projects, but also bring many potential benefits to nuclear power projects. This study uses a nuclear power plant reactor building as a case study to analyze the impact of base isolation technology on seismic performance. A detailed three-dimensional finite element model of the reactor building was established, and dynamic time-history analysis was conducted to calculate the seismic response of isolated and non-isolated structures. The influence of base isolation on structural acceleration and displacement response was then compared and analyzed. The results indicate that implementing base isolation decreases the structure's natural frequency and increases its period; structural acceleration response is significantly reduced in the isolated structure; while overall displacement of the structure with isolation measures increases, relative displacement within the upper structure remains minimal, with most displacement occurring in the isolation layer. Compared to structures without isolation measures, base isolation technology effectively reduces seismic impacts.