Abstract: A thermodynamic simulation program for Nb powder production process by hydrogen reduction of NbCl₅ in argon was developed by using SimuSage Software, which is a component library used in the developing of process simulation. The effects of the key parameters such as evaporation temperature, loading gas amount (Ar(g)), reduction temperature, He (g) amount and collection temperature were studied by the simulation program. The results show that the evaporation rate of NbCl₅ (s) and the content of NbCls(g) in gas are dependent upon the evaporation temperature and the amount of Ar(g) used. To get Nb(s) as the unique solid product, a minimum H₂ (g) amount of 20 mol per mol NbCls is needed when the reduction temperature is 1000℃. High temperature of collection is helpful to the purity of the solid Nb powder product.