Al2TiO5 powder prepared by the sol-gel processing from the metal alkoxides ; aluminium sec-butoxide (Al(OC4H9)3 and tetraethyl orthotitanate (Ti(OC2H5)4) was very fine and had a narrower particle size distribution than that prepared from the commercial alumina and titania powders. The addition of mullite and Al2O3 powder to Al2TiO5 inhibited the grain growth and this resulted in decrease of microcracks and increase of fracture strength. Al2TiO5/ mullite composite showed the higher fracture strength than Al2TiO5/alumina composite. The thermal expansion of Al2TiO5 increased with the addition of mullite and alumina and also increased with tempe-rature up to 100$0^{circ}C$ however it decreased in the temperature range between 100$0^{circ}C$ and 125$0^{circ}C$ during during heating The decomposition test showed that the addition of mullite suppressed the decomposition of Al2TiO5 on the contrary the addiion of Al2O3 accelerated the decomposition of Al2TiO5