Abstract: Gallium is a rare scattered metal of important uses.The V-containing slag produced by Panzhihua Steel Co.contains Ga₂0₃.In this paper,the influence of the p_O2 on extracting Ga from the V-containing slag is discussed based on thermodynamic analysis and experimental results.The predominance diagram of the V-Ga-Cl-O system at 850℃ indicates that,during roasting,a relatively high O₂ partial pressure should be maintained to oxidize FeV₂O₄ which then reacts with NaCl and liberates Cl₂ to chloridize Ga₂O₃ in the slag.It was found from the roasting experiment that the chlorination ratio of Ga₂O₃ increases with p_O2 when p_O2 is lower than 0.005 MPa but decreases with p_O2 when p_O2 is higher than 0.005MPa.The maximum chlorination ratio of Ga₂O₃ during roasting was about 31%.