Abnormal gas sensing characteristics are observed at low temperature in uniformly loaded Pt@SnO(2) nanorod gas sensors. The sensors operated at 200 degrees C exhibit opposite variations of resistances, and the change of resistance decreases with increasing ethanol concentration. In contrast, the sensors operated at 300 degrees C show regular behavior and the sensitivity is extremely high. Such behaviors are ascribed to Pt-catalyzed morphological changes of ionsorbed oxygen at low temperature. The present results are the bases for further investigating the effect of ionsorbed oxygen morphologies on gas sensing.