Abstract： Objective To investigate the mechanisms of taurine(Tau) preventive effect on neurotoxicity induced by manganese (Mn) in rat's prefrontal cortex. Methods SD rats were divided into four groups after one week of observation: normal control:the group animals received daily intraperitoneal (ip.) injections of sterile saline for 3 months; Mn treated group (Mn): rats received ip. injection of MnCl2·4H2O once a day for 3 months;Tau preventive group (Mn+Tau):The Mn level of this group were the same as Mn's,the Tau level 200 mg/kg,three times per week, for 3 months;Tau treated group(Mn→Tau): After received the daily injection of Mn as Mn group for 3 months,the rats received Tau three times per week for 3 months. The dose of Mn and Tau were the same as above. The experiment lasted 6 months. Results (1)Mn induced apoptosis of neurons in rat's prefrontal cortex. The ratio of apoptosis of neurons in the Mn treated group [(20.0±4.3)%] was higher than that of the control group [(1.8±2.1)%](P<0.05) and the ratio of apoptosis in Tau preventive group (Mn+Tau) was lower than that of the Mn treated group (P<0.05). (2)The production of MDA in Mn treated group was higher than the control group (P<0.05) and the activity of SOD was lower than that in the control group. In Tau preventive group(Mn+Tau), Tau increased the activity of SOD and decreased the production of the MDA, with the significant difference level compared to the Mn treated group(P<0.05). Conclusion Mn induces apoptosis in rat's prefrontal cortex neurons. The main mechanisms of Tau preventing eytoxicity against Mn is the reduction of the oxidative stress in prefrontal cortex neurons.