A new processing route is presented for  preparation of VFeSb-based Half-Heusler alloys in bulk with glass fluxing technique, which effectively leads to grain refining, increase of lattice defect density and  the volatilization inhibition of Sb. Interestingly, the phase transition of VFeSb from fcc to hcp is found in the ingot with undercooling of 40K when compared to the ingot with undercooling of 0k. And the lower thermal conductivity is shown in the ingot with undercooling of 40K, resulting in the higher dimensionless figure of merit ZT. Furthermore,  VFeSbNbCoSn-based Half-Heusler alloy is successfully obtained by the glass fluxing technique,which enhance the thermoelectric properties of pure VFeSb ingot by doping NbCoSn components.