Mo–Si–B nanocomposite powders with a composition of Mo–12Si–8.5B(in at.%) were processed using mechanical alloying under milling conditions for different milling time and powder-to-ball ratios. The Mo–12Si–8.5B alloy, which consists of α-Mo and intermetallic Mo3 Si and T2 phases, was also synthesized by hot-pressed sintering the mechanically alloyed powders under a pressure of 50 MPa at 1600 °C.The results demonstrated that the sizes and morphologies of the powder particles became gradually refined and uniform by both increasing the milling time and decreasing the powder-to-ball ratio. After 15 h of milling, the powders were completely homogenized at the 1:10 and the 1:15 powder-to-ball weight ratios,and the homogenization was accelerated to rapidly stabilize the milling process because of their high milling energy. Annealing the Mo–Si–B milled powders could promote the growth of the intermetallic Mo3 Si and the T2 phases, which formed even after low-temperature annealing at 900 °C. Increasing the annealing temperature only improved the crystallinity of various phases. When the milled and annealed powders were hot-pressed sintered, the Mo–Si–B alloy exhibited a fine-grained microstructure,where the intermetallics Mo3 Si and T2 were distributed in a continuous α-Mo matrix. Mo-Si-B nanocomposite powders with a composition of Mo-12Si-8.5B (in at.%) Were processed using mechanical alloying under milling conditions for different milling time and powder-to-ball ratios. The Mo- alloy, which consists of α-Mo and intermetallic Mo3 Si and T2 phases, was also synthesized by hot-pressed sintering the mechanically alloyed powders at a pressure of 50 MPa at 1600 ° C. The results demonstrated that sizes and morphologies of the powder particles became gradually refined and uniform by both increasing the milling time and decreasing the powder-to-ball ratio. After 15 h of milling, the powders were completely homogenized at the 1:10 and the 1:15 powder-to-ball weight ratios , and the homogenization was accelerated to rapidly stabilize the milling process because of their high milling energy. Annealing the Mo-Si-B milled powders could promote the growth of the intermetallic Mo3 Si and the T2 phases, which formed even after low-temperature anneal ling at 900 ° C. Increasing the annealing temperature only only the crystallinity of various phases. When the milled and annealed powders were hot-pressed sintered, the Mo-Si-B alloy exhibited a fine-grained microstructure, where the intermetallics Mo3 Si and T2 were distributed in a continuous α-Mo matrix.