Abstract: The yield strength and creep curves of TiAl PST crystals with two ′hard′ orientations( i.e. , φ =90° and 0°, φ is the angle between loading axis and lamellar boundaries) at high temperature have been measured and compared, and the deformation structures of the crept samples have been examined by using SEM and TEM. The results indicated that the yield strength and creep behavior were quite different between these two oriented samples; Under the condition of T =800℃ and σ =350MPa, the earlier onset of tertiary creep was found in the sample with φ =90°, which may be caused by the spheriodization of α 2 phase and the formation of shear band during creep.