In the present study, we report the hydrogen sensing properties of sputter deposited trilayers, multi-layers and alloy thin film of Pd and Mg materials. The change in electrical resistance is found to be reversible at room temperature during hydrogenation/dehydrogenation process for both the multi-layers and alloy thin film. The response time for Pd/Mg/Pd tri-layers, Pd/Mg/Pd/Mg/Pd multi-layers and Pd/Mg-Pd alloy is 4.5, 3.5 and 3 s, respectively. The hydrogen desorption from Pd/Mg/Pd/Mg/Pd multi-layers is enhanced by "cooperative effect" caused by elastic interaction within interfacial region of Pd and Mg films. While, the room temperature desorption with fast kinetics for Pd-capped Mg-Pd alloy thin film is due to reduction in binding energy. The study suggests that these Pd-Mg based alloy thin film and multilayers have the potential to be used as room temperature H-2 gas sensor. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.