Abstract: In this paper, extracted conditions, purified and character analyzed superoxide dismutase (SOD) from Hybrid tilapia(Oreochromisniloticus×Oreochromisaurea) liver with heat treatment, followed by acetone precipitation and HitrapTM Q FF anion chromatography were studied. The results showed that the fine SOD extracting conditions were: Joins 10mmol/L CuCl2 in the cushion fluid, and adjust pH 5.6, heat treatment temperature 65℃. The yield of rough SOD is 57% and specific activity is 2580±6U·mg-1.The purified SOD obtained from tilapia liver is pale blue –green in color and specific activity is 4895±2 U·mg-1. It is a sole proteinase belt and the molecular weight is 36000 daltons as determined with SDS-PAGE electrophoresis. There is a special ultraviolet absorption spectrum at 265nm. It is stable below 75℃ and at pH6.0～9.0. The effects of some inhibitors on the activity of Cu,Zn-SOD showed that the potassium cyanide, urea, β-mercaptoethanol, hydrogen peroxide and EDTA (which concentration is above 3 mmol·L-1 )can obvious inhibit the enzyme, EDTA (which concentration is below 3 mmol·L-1) and DDT can activate the enzyme. Further work should be carried out on the sequences of the enzymes and the applications. Key words: hybrid tilapia(Oreochromis niloticus♀×Oreochromis aurea♂)； liver； superoxide dismutase（SOD）； heat treatment； purification