Base　isolation　technology,　as　a　mature　seismic　mitigation　method,　demonstrates　potential　for　enhancing　seismic　margins　in　nuclear　power　plant　structures.　This　study　investigates　the　seismic　performance　of　isolated　and　non-isolated　models　for　a　diesel　generator　building　in　a　nuclear　power　plant　through　shaking　table　tests.　A　1/8-scale　structural　model　was　designed　and　tested　under　operational　safety　ground　motion　(SL-1),　ultimate　safety　ground　motion　(SL-2),　and　beyond　design　benchmark　ground　motion　(BDBE)　seismic　excitations.　A　finite　element　model　considering　different　tensile　and　compressive　stiffnesses　of　isolation　bearings　was　established　to　simulate　structural　dynamic　responses　under　test　conditions.　The　results　demonstrate　that　the　test　model　design　is　effective,　with　the　maximum　isolation　rate　was　close　to　50%.　The　maximum　displacement　of　the　isolation　layer　meets　the　collision　prevention　ditch　limit.　Numerical　simulations　showed　good　agreement　with　experimental　results　in　acceleration　time　histories,　displacement　time　histories　and　bearing　hysteresis　curves.　Additionally,　the　seismic　isolation　structure　has　a　certain　overturning　effect　in　the　test.　To　further　optimize　the　base　isolation　scheme,　numerical　analyses　incorporating　dampers　into　the　isolation　layer　were　conducted,　which　demonstrated　improvements　in　mitigating　the　rocking　effect　of　the　superstructure.