The results showed that: the content of MDA was increased, while the activity of SOD was decreased in the APP/PS1 mice cortex; the ROS level was increased in SH-SY5Y cells treated with AβO; the expression of Nrf2-ARE signal pathway-associated proteins such as Nrf2, HO-1, SOD2 and NQO1 in APP/PS1 mouse cortex and in SH-SY5Y cells treated with Aβ were reduced significantly, which was consistent with previous reports, indicating that Aβ-induced OS was a main mechanism in the pathogenesis of AD. The gene discussed is APP; the disease is Alzheimer disease.