Mechanical properties of in-situ toughened Al2O3/Fe3Al nano-/micro-composites were measured. Effects ofFe3Al content, sintering temperature and holding time on properties and microstructure of the composites wereinvestigated. The addition of Fe3Al nano-particles decreased the aspect ratio and grain size of Al2O3, and changedthe fracture mode of composites. The maximum bending strength and fracture toughness were 832 MPa and 7.96 MPa m1/2, which were obtained in Al2O3/5 wt.% Fe3Al sintered at 1530 8C and Al2O3/10 wt.% Fe3Al sintered at 1600 8C, respectively. Compared to monolithic alumina, the strength increased by 132% and the toughness increased by 73%. The improvement in the mechanical properties of the composites was attributed to the change in fracture mode from intergranular fracture to transgranular fracture, the "'in-situ reinforced effect" arising from the platelet grains of Al2O3 matrix, refined microstructure by dispersoids, as well as crack deflection and bridging of intergranular and intragranular Fe3Al.