Ti-Al intermetallic composile with Al2O3 fiber interpenetration was fabricated in situ in slight-oxidizing atmosphere by the heat-treatment of the prefabricated pieces consisted of Ti, Al and other trace metallic elements. The final phases composition and mierostrueture were analyzed by XRD and SEM. The principle of the synthesis process and the influertce of the processing parameters on the mierostructure development were investigated in order to study whether the Al2O3 fiber would exist and what kind of matrix phases would be formed easily according to the molar ratio of components and the processing parameters.