A series of TiBw-Ti6Al4V composites with very low volume fraction (0.25%-2.0%) of reinforcement were successfullyfabricatedby powder metallurgy process. In the fabrication process, the TiB2 powders asboron source were adheredonto the surfaceof Ti6Al4V powders in the low energy milling process, and then, the TiB whisker reinforcement were in situ synthesized by thereaction between TiB2 and Ti. It is surprised to find that not only the tensile strength but also the ductility of the as-sintered0.25vol.% and 0.5vol.% TiBw-Ti6Al4V composites are higher than those of the as-sintered Ti6Al4V alloy. It is worth pointingout that the yield strength (787MPa), ultimatetensile strength (885MPa) and the tensile elongation (14.3%) of the Ti6Al4Valloy are certainly reasonable. However, the 0.25vol.% TiBw-Ti6Al4V composites exhibit 975MPa of ultimate tensile strengthand 22.8% of tensile elongation. In addition, it is reasonable that the tensile strength increases while the elongation decreaseswith increasing volume fractions of TiB whisker. The 2.0vol.% TiBw-Ti6Al4V composites exhibit 1070MPa of ultimate tensilestrength and 9.1% of tensile elongation. The superior tensile properties of the as-sintered TiB-Ti6Al4V compositesare related tonot only grain refinement but also novel deformation and fracture mechanisms.