Abstract: Considering that the recovering V₂O₅ by roasting leads to some serious problems such as environment pollution,high energy consumption and low conversion efficiency at present,the influencing factors of leaching vanadium from ore with the composite sodium agent are studied in this paper by sub-molten salt method.The investigation involves many hands including analyzing the primary and secondary relations of these factors by orthogonal test,and further researching the effects of liquid-to-solid ratio,the adding content of chloride salts and reaction time on vanadium leaching efficiency.The results show that the leaching efficiency of V₂O₅ is higher than 90% in the condition of agent concentration 70%,liquid-to-solid ratio 5:1,the ratio of chloride salts 45 and reaction time 2.5 h.Taking sub-molten salt method can resolve some problems to recover V₂O₅ caused by roasting,and provide a new way for extracting V₂O₅ from wet process.