Abstract: Physiochemical properties and their activity, selectivity of a series of aluminum silicate catalysts for MTBE cracking to isobutene were examined by catalytivity test, XRD, physical adsorption and FT-IR. The results showed that the addition of suitable promoter and calcining at an appropriate temperature could improve the physiochemical properties and activity of the catalyst. In all properties measured in this paper, specific surface area, total acid amount and the ratio of Bronsted acid to Lewis acid could have close relations with catalystic activity. It was also found that the MTBE conversion and isobutene selectivity over the catalyst named WVI were 99.9% and 99% respectively under the conditions of atmospheric pressure, 2 h－1 and a wide temperature range from 220 ℃ to 360 ℃.