The decomposition of isopropyl alcohol was chosen as a probe reaction of acid-base property of molybdena-alumina catalyst. The catalytic kinetics was examined on the oxidized catalyst. The kinetics of the dehydration （yielding propene） and the dehydrogenation (yielding acetone) obeyed the Langmuir-Hinshelwood mechanism in which the rate determining step is the desorption of water for the former and the sur face reaction for the latter, respectively. The effect of varying the extent of reduction of the catalyst was also studied. The trend of variation with the reduction was fairly consistent with the surface chemistry of the catalyst.