A new preparation method for hexa-aluminate-based catalysts to be used in high temperature catalytic combustion was studied. BaOㆍ6$Al_2O_3$, BaMn$Al_{11}O_{19}$, $Sr_{0.8}La_{0.2}MnAl_{11}O_{19}$ catalysts were prepared by freeze-drying of aluminum hydroxide sol dispersed in the solution of metal nitrates. Physico-chemical characterization data are given for samples calcined at different temperatures through XRD, $N_2$ adsorption, SEM, and $^{27}Al$ solid state NMR. Hexa-aluminate structure was formed at 1200℃ in the case of $BaAl_{12}O_{19}$. Mn showed the promoting effect in the formation of hexa-aluminate structure. Needle-like crystals were observed from $Sr_{0.8}La_{0.2}MnAl_{11}O_{19}$ above 1000℃ which seemed to suppress the sintering of primary particles by minimizing crystal-crystal contact. Methane combustion reaction was carried out in a continuous micro flow reactor with a fixed bed under various contact time. $Sr_{0.8}La_{0.2}MnAl_{11}O_{19}$ prepared from freeze-dried gel which had been mixed with nitrate solutions showed higher activity than that from xerogel.
