Abstract: The hot V slag were first oxidized ouly 10 odd min.with blowing oxygen and then were alkaline leached,the leaching ratio of V come up to 90%.Higher C_Fe³⁺/C_Fe²⁺ can be obtained in case of increasing the addition of CaO into V slag,weight ratio of MgO and slag is controlled in optimum range, and decreasing the rate of oxygen supply in blowing oxygen process,Leaching ratio of V increases major with the increases of C_Fe³⁺/C_Fe²⁺. Holding time,leaching temperature,the addition ratio of Na₂CO₃,and NaOH,and the weight ratio of slag and water influence the leaching ratio of V.The total leaching ratio of V increases with the oxygenation during V slag alkaline autoclave leaching and during residuel slag water leaching.