Thermoelectric properties of pure,Cd-and In-doped ZnSb are studied by first principles calculations of electronic structures and the semi-classical Boltzmann transport theory.The doping of Cd or In at the Zn lattice site slightly increases the lattice parameters due to the larger atomic radii of Cd and In compared with that of Zn.Cd or In doping also apparently increases the interatomic distances between the dopant atoms and the surrounding atoms.The power factor of n-type ZnSb is much larger than that of p-type ZnSb,indicating that n-type ZnSb has better thermoelectric performance than p-type ZnSb.After the doping of Cd or In,the power factor reduces mainly due to the decrease of the electrical conductivity.The temperature dependences of the Seebeck coefficient and the power factor of pure,Cd-and In-doped ZnSb are related to carrier concentrations.