Abstract: To get a reasonable, simple and efficient purification process of superoxide dismutase (SOD) from tilapia blood, the purification conditions of SOD by ion exchange chromatography (IEX) were explored and optimized.At last, the optimized purification conditions of SOD were fixed as follows:the mobile phase was pH8.0 20mmol/L Tris-HCl buffer, the stepwise elution method was 10%B、20min→30%B、15min→100%B、15min, the optimum sample volume was 4mL and the maximum flow rate was 150cm/h.The results showed that the specific enzyme activity of the purified tilapia blood SOD was 4052U/mg protein with a yield of 59.7% and a purification fold of 942 times, respectively.The optimized purification technology of SOD could provide a scientific and reliable technical guidance for future purification research and commercial process of SOD.