The W-modified Ti2AlNb-based alloys synthesized at 1100����C by spark plasma sintering were solution treated at 1300����C for 4��h and then aged at 800���1000����C for 1��h. The phase composition, microstructure evolution, and microhardness of the aged alloys are investigated in this study. A significant enhancement of hardness, ~ 750��HV, is obtained in the alloy aged at 900����C, while that of the one without W addition is only ~ 470��HV. The hardness is also higher than that of common ��-Ti and Ti���6Al���4V alloys. As the ageing temperature increases, the B2/O structure evolves from B2 + O colonies to Widmannst��tten structure, followed by a ���disordering to ordering��� procedure. This process also involves the variation of the angle between adjacent O phase from 90�� to 60��. Specifically, a herringbone Widmannst��tten B2 + O structure is constructed in the alloys aged in the ��2 + B2 + O phase region, which is related to the diffusion of W and the substitution of W for Nb in the lattice of B2 or O.