Reverse micro emulsion method showed some advantages in the preparation of the catalyst MnBaAl11O19-δ with large surface area and high activity, when compared with sol-gel method or co-precipitation method. The influences of water content in reverse micro emulsion on nanostructure catalyst MnBaAl11O19-δ were discussed in this paper. The catalyst MnBaAl11O19-δ was prepared by reverse microemulsion method with a system consisted of 55% of n-heptane, 15% of emulsifier OP-10, 15% of 1-octanol and 15% of water (volume ratio). It resulted in the catalyst a length of 10-30nm plated-like phase and large surface area of 106 m2/g. The catalyst was applied in dimethyl ether combustion and it showed high activity with T10% at 160 °C and T90% at 300 °C. The recycle reverse micro emulsion was reused to prepare the catalyst MnBaAl11O19-δ. The catalyst MnBaAl11O19-δ prepared with that, still showed large surface area of 65m2/g and high activity with T10% at 170 °C and T90% at 320 °C in dimethyl ether catalytic combustion.