Abstract: Half-Heusler alloy has attracted much attention in the field of medium and high temperature thermoelectric power generation because of its good thermoelectric properties, good mechanical properties and high thermal stability. In order to understand the influence of changing the ratio of Fe to Ni on the thermoelectric properties of samples of half-Heusler alloy TiFe_xNi_1-xSb (x = 0.4, 0.5, 0.6), the samples were prepared by arc melting, high-energy ball milling and fast DC hot pressing, and their conductivity types and carrier concentrations were determined respectively. The experimental results show that the carrier concentration at room temperature can be increased by changing the ratio of Fe to Ni in the alloy, and the carrier concentration at room temperature of TiFe_0.6Ni_0.4Sb sample is the highest, which is 5.33×10²¹ cm³, and lower lattice thermal conductivity at 973 K of about 3.18 W m^–1 K^–1. It shows that changing the proportion of Fe and Ni elements in the alloy is an effective method to optimize thermoelectric properties.