We have studied the adsorption reaction of (CH₃)₂S on Rh/Al₂O₃/NiAl(100) and sulfur removal reaction depending upon heat-treatment using X-ray Photoelectron Spectroscopy and Atomic Force Microscopy techniques. The results show a difference in the adsorption reaction between the as-deposited Rh/Al₂O₃/NiAl(100) and that heat-treated at 1000 K. (CH₃)₂S dissociates on the Rh/Al₂O₃/NiAl(100) as-deposited surface at 300 K, and the sulfur removal reaction occurs at 523 K induced by O₂ dosing. In contrast, the heat-treated surface is quite inert against the dissociative reaction of (CH₃)₂S, because the Rh atoms dissolute into the NiAl(100) substrate through the Al₂O₃ layer by the high temperature treatment (1000 K). The AFM results also show the morphological changes in these systems, such as many stripe structures for the Al₂O₃/NiAl(100), nanoclustered surface for the Rh/Al₂O₃/NiAl(100) as-deposited surface, and nano-hole structures for the Rh/Al₂O₃/NiAl(100) heated at 1000 K. [DOI: 10.1380/ejssnt.2009.239]