To study the function of peanut nutrient oil supplemented with DHA algae oil and AA oil, SD rats were gavaged with peanut oil supplemented with different dose of DHA algae oil and AA oil, respectively the effects on monoamine oxidase activity in cerebral cortex and liver cell were examined after 8 weeks of continuous feeding. The results showed that the control group fed with peanut nutrient oil had significant difference compared with the normal peanut blending oil group (P<0.01). Peanut nutrient oil containing DHA algae oil and AA oil can significantly reduce the activity of monoamine oxidase in the cerebral cortex of SD rats, and effectively improve the symptoms of liver edema and cell inflammation in middle-aged SD rats, and slow down the rate of cell death. It can be speculated that the intake of appropriate amounts of DHA and AA can potentially reduce the risk of liver cirrhosis and fibrosis in the elderly people, and achieve the role of protecting the liver.