The equilibrium composition of V2O5 and reductant during direct alloying of V2O5 as a complex system composed of muti-component and multi-phase were simulated by HSC and then analyzed.The result of thermodynamic calculation shows that the reduced products of V2O5 carbothermic reduction is the carbide of vanadium,the system of silicothermic reduction should add CaO,aluminothermic reduction can reach a reduction rate of 99%,the reduction ability of Al is more effective than that of C and Si.The complex silicothermic and aluminothermic reduction can reach a high reduction rate by using a small quantity of Al,the calculation result is consistent with the thermodynamic law of the industrial practice of making ferrovanadium by electricity -silicothermic method.