The abnormal IR effects(AIREs) of the adsorption of CO on electrodes made of Pt nanostructured thin films generated in square wave potential treatment were obs erved. Based on the experimental results, the AIREs were analysed and simulated by taking into consideration of the interparticle interaction and the electron- hole damping. The results illustrate that the islanded nanostructured Pt surface s give rise to the interactions between CO molecules as well as between CO molec ules and nanostructured Pt surface. The energy transfer due to electron_hole dam ping and the enhancement of interparticle interaction are the important cause of the changes of IR absorption spectra.