A series of WO3-promoted Cr2O3-based catalysts were prepared and tested for the simultaneous dehydrogenation and isomerization of n-butane to isobutene. It is found that a Cr2O3/WO3-ZrO2 system is an effective catalyst for this reaction; however, the catalytic behavior is dependent on Cr2O3 and WO3 contents, space velocity and temperature. 10 wt% Cr2O3/20 wt% WO3-ZrO2 can give high initial conversion and isobutene selectivity, but it deactivates rapidly due to the variation of surface properties and pore structure caused by carbon deposition.