Due to the existence of scaling properties of adsorption energies on transition metal surfaces, the enhancement of the catalytic activity is frequently accompanied by side reactions leading to a reduction in selectivity for the target product. Herein, by systematically screening Pt alloy materials using density functional theory calculations, we developed an approach to breaking the scaling relationship for propane dehydrogenation, an industrially important reaction, by assembling single atom alloys (SAAs), to achieve simultaneous enhancement of propylene selectivity and propane conversion. We synthesized γ-alumina-supported platinum/copper SAA catalysts using a modifiedby incipient wetness co-impregnation method with a high copper to platinum ratio. Single platinum atoms dispersed on copper nanoparticles dramatically enhance the desorption of surface-bounded propylene and prohibit its further dehydrogenation, resulting in high propylene selectivity. The reported discovery will open the exploitation of Pt/Cu SAA as promising active sites for alkane dehydrogenation at relatively high temperature.