Abstract: TaFeSb-based half-Heusler alloys were prepared by high-energy ball milling combined with DC rapid hot pressing. It is proved that TaFeSb is a p-type thermoelectric material. In this paper, the effects of Ti doping in Ta site on the thermoelectric properties of TaFeSb were investigated. The experimental results show that Ti doping decreases the thermal conductivity and increases the electrical conductivity of the samples, and the Seebeck coefficient decreases slightly with the increasing content of Ti. Consequently, the power factor shows a significant improvement after Ti doping, and the ZT value of Ta_1-xTi_xFeSb alloy has been obviously increased. Finally, a maxmium ZT value of 0.8 has been achieved for Ta_0.80Ti_0.20FeSb sample at 973 K.