Abstract: Square bars of a Ti-46Al-4Nb-0.5Mo-0.08B alloy with fine grains and a homogeneous microstructure were successfully fabricated via two-step canned extrusion with a large accumulative extrusion ratio, providing high-quality preforms for subsequent forging of TiAl alloy blades. The microstructural evolution of the bars during the two-step extrusion process was systematically investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results indicate that after the first extrusion, a considerable number of residual lamellar structures remained in the bar, with a noticeable difference between the center and edge regions. Following the second extrusion, the original coarse lamellae were essentially eliminated, and complete dynamic recrystallization occurred, resulting in a uniform near-γ microstructure. Only a minimal amount of B2 phase precipitated at the grain boundaries during cooling after extrusion. The obtained bars exhibited a room-temperature yield strength of 705 MPa with an elongation of 3.32%, and a yield strength of 474 MPa with an elongation of 32.75% at 760 ℃. The fine grain size and the minimal B2 phase content contribute to the favorable room-temperature ductility of the bars.