Ti-45Al-3Fe-2Mo-0.2Er (at.%) pre-alloying powders were fabricated by PREP, and then were consolidated by SPS. The solidifying features and the resulted microstructures were observed. The results show that, the phase and the exterior and interior microstructure of alloying powder are related with its size. The solidified microstructures of powder surface with particle size more than 105μm are dendritic, its phase is hexagonal α2 phase with a small amount of γ phase containing; while the powder surface with particle size less than 75μm has smooth surface microstructures, its phase is hexagonal α2 phase, and a small amount of B2 phase is also contained inside. For the compacts prepared via SPS method, there are the previous particle boundaries and local coarsening lamellar microstructure. It is obviously that the formation of such two structures shows genetic correlation with the microstructure and phase structure of large-size powder particles.