Removal of tooling by electrolysis was one of the key procedure in hot isostatic pressing （HIP） of complex titanium alloy components. Based on the current studies， there were few works on the properties of titanium alloy prepared by HIP in sulfuric acid environment.The effects of different electrolysis time on the performance of HIP TA15 titanium alloy such as surface passive film， hydrogen content and mechanical properties under 40% sulfuric acid environment were studied. The results show that the thickness of passive film on the surface of TA15 titanium alloy increases gradually at 15， 30， 45， 60 d respectively， and reaches to 175.3 μm at 60 d.The increase of hydrogen content is not significant at 15 d with an average of less than 2×10^-5.After 30 d， the average hydrogen content increases remarkably and reaches to 5.4×10^-4 at 60 d. The yield and tensile strength of HIP TA15 titanium alloy decreases gradually with the prolonging of electrolysis time， while the plasticity is basically unchanged. The surface qualities and mechanical properties of HIP titanium alloy are effected by the time of electrolysis in sulfuric acid environment， subsequent process control need to be strengthened.