Abstract: The optimum ball milling process was determined by orthogonal design, and Ta-Al mixed powder was mechanically alloyed by optimized process. XRD and SEM were used as the main characterization methods to study the effect of ball milling time and composition change on Ta-Al alloying process. The results show that the ball milling time has the most significant effect on the grain refinement, while the solid-liquid ratio has less influence on the experimental range. The comprehensive analysis considers the best ball milling process combination: ball to material ratio 10:1. The solid-liquid ratio is 1:0.5, the ball milling speed is 300r/min, and the ball milling time is 36 h. After high energy ball milling for 8 h, Ta-Al system is basically alloyed. Part of Al diffuse into the Ta to form a replacement solid solution, and continue to ball mill diffraction peak broadening and peak strength reduction. When Ta-10wt%Al, no Al diffraction peak is detected, and the single-phase structure is obtained. After calculation, 28.9at% Al is solid-dissolved into Ta under the combined driving of thermodynamics and kinetics to form a supersaturated solid solution, and the remaining Al is dispersed in the nanocrystalline boundary of Ta.