In this work the effect of heat treatment on microstructure of Ti-48Al-4Cr(at.%) alloy rapidly solidified at the wheel speed of 10m/s were experimentally investigated by using the single roller melt-spinning technique. The results indicate that after rapid solidification, the microstructures mainly consist of equiaxed γ phase, few volume fraction of α2, B2 phase particles and lamellar structures exists in the γ phase matrix. After heat treament at 723℃/1h, α2 particles becomes unstable. Annealing at 932℃ for 1h, the α2 plate in lamallar strucctures becomes unstable. The α2 plate in the lamellar structures is subdivided into rod-shaped α2 phase and α2 particles. Annealing at 995℃/1h, large volume fraction of lamellar structures dissolved, however, rod shaped α2 phase still exists. B2 phase is being precipatated at the grain boundary. This research has provided the basis of further studying on the microstructures and phase transformation of rapidly solidified Ti-Al intermetallics and enriched the theory of rapid solidification.