In this work, a Ti2AlNb based intermetallic alloy with the composition of Ti-22Al-24Nb-0.5Mo(atomic fraction, x/%) pre-alloyed powder was produced by electrode induction melting gas atomization, and its chemical composition, surface state and fluidity were characterized. The powder metallurgy(PM) Ti2AlNb alloy was fabricated by hot isostatic pressing. The effect of vacuum degassing on mechanical properties of PM Ti2AlNb alloy was studied. The results show that the batch stability of chemical composition of Ti2AlNb alloy powder is good. Considering the process performance of powder filling, the principle of powder size selection is to select full size distribution pre-alloyed powder with particle size less than 250 μm. Vacuum degassing can reduce the pore defects of PM Ti2AlNb alloy. Vacuum degassing can improve the stability of tensile properties and rupture lifetime of PM Ti2AlNb alloy at elevated temperature.