Abstract: Using Beckman electrolyte and automatic biochemical analyzer, we compared the blood index, and the activity of antioxidant enzyme in muscle and liver under different circumstance . It turned out that under sea and fresh water environment, the content of glutamic pyruvic transaminase（GPT）are significantly different（P<0.05）, so are the contents of aspartate transaminase（GOT）. The contents of fish in GDT and GOT in freshwater are higher than those of seawater, the values are （7.00±2.82）μ/ L and（44.00±7.43）μ/ L, respectively, which are 1.36 times and 3.35 times of the seawater group. The trace element potassium （K+）, sodium （Na+）, chlorine（Cl-）, calcium （Ca2+) and albumin（A）, triglycerides and globulin（G）in sea wafer fish are greater than those in freshwater group. Total cholesterol levels were markedly different（P <0.05）, the level of seawater group is greater than that of freshwater group. Hemoglobin, platelet hematocrit, number of red blood cells, platelet count of fishes in seawater are obviously higher than those in freshwater group, which decreased by 68.31%, 37.32%, 22.58% and 24.29%, respectively; The width of platelet distribution and red blood cell distribution and the hematocrit is apparently different（P<0.05）.

Key words: rainbow trout, the blood index, antioxidant enzymes