Al₂O₃ short fiber (containing 28 vol.% SiO₂) reinforced TiAl matrix composite was prepared by spark plasma sintering (SPS). The interfacial reaction mechanism was clarified by thermodynamic and kinetic analyses. The main interfacial phase was Ti₅Si₃, originated from Ti element of TiAl matrix and Si element of Al₂O₃ fiber. The activation energy of interfacial layer was 285.1 kJ/mol. In addition, the matrix around the interfacial region was composed of γ-TiAl phase due to the consumption of Ti element in the process of interfacial reaction. However, the formation of mullite phase occurred in the heat-treated Al₂O₃ fiber and as-sintered composite due to the chemical reaction between γ-Al₂O₃ and amorphous SiO₂ phases.