Geotechnical seismic isolation (GSI) system involves the dynamic interaction between structure and low-modulus foundation material, such as rubber-soil mixtures (RSM). Whilst numerical studies have been carried out to demonstrate the potential benefits of GSI-RSM system, experimental research is indispensable for confirming its isolation mechanism and effectiveness in reducing structural demand. In this regard, centrifuge modelling with an earthquake shaker under an acceleration field of 50 g adopted in this study can mimic the actual nonlinear dynamic response characteristics of RSM and subsoil in a coupled soil-foundation-structure system. This is the first time the performance of GSI-RSM system was examined in a geotechnical centrifuge. It was found that an average of 40-50% reduction of structural demand can be achieved. The increase in both the horizontal and rotation responses of the foundation was also evidenced. The unique augmented rocking mechanism with reversible foundation rotation was highlighted.