Abstract: To investigate the effects and possible molecular mechanism of S-oxiracetam(S-ORC) on learning and memory impairment in mice, mice were divided into 5 groups, control group, model group, high-dose of S-ORC (0.96 g/kg), medium-dose of S-ORC (0.48 g/kg) and low-dose of S-ORC (0.24 g/kg) treatment groups.Step-down test and Y-maze test were used to investigate the effects of S-ORC on the brain.The results of step-down test revealed that the mice in high and medium-dose groups could significantly decrease the reaction time, fault times and prolong the incubation periods of memory compared with the model group.Compared with the model group, the fault times of mice in high and medium-dose groups decreased significantly and the right times to find the safety increased significantly in Y-maze test.Furthermore, through treatment with S-ORC (high and medium-dose groups), the content of Ach in mice brain was significantly higher than that in model group, and the level of AChE decreased significantly.The above results suggest that the underlying mechanism of S-ORC on learning and memory impairment in mice may include the amelioration of the central cholinergic nervous system.