Developing sensitive and stable hydrogen sensors is of great importance for sustainable energy development. Here, a novel hydrogen sensing platform is described based on colloidal clusters of Au@Pd core-shell nanoparticles (Au@Pd NPCs) with characteristic localized surface plasmon resonance (LSPR) properties. Au@Pd NPCs with well-controlled topologies exhibit highly pronounced sensitivity for LSPR-based hydrogen sensing in aqueous solution in comparison to their nanoparticle counterparts and previously reported Au-Pd bimetallic nanostructures, which can be attributed to highly promoted plasmonic field resulting from the cluster formation. Furthermore, Au@Pd NPCs show stable sensing capability for repeated hydrogen sensing cycles. The present strategy for devising high-performance LSPR-based hydrogen sensors via the controlled assembly of bimetallic nanoparticles can be applied to the development of efficient plasmonic platforms for various sensing applications.