Abstract: The oxidative acid leaching process of Co white alloy containing high silicon is studied. The influences of leaching agent, oxidant dosage, molar ratio of H₂SO₄/HCl, liquid-solid ratio, leaching temperature and time on leaching rate of cobalt and copper are investigated. The results show that more than 99 % of Co, Fe, Cu can be leached under the following conditions: initial acidity 5.0 mol/L, mole ratio of H₂SO₄/HCl 8:2 as leaching agent, excess coefficient of acidity 1.2, excess coefficient of oxidant (NaClO₃) 1.4, leaching temperature 70 ℃ for 2 h. Leaching slurry is easy to be filtrated with no cuprous chloride precipitation and silica gel.