To observe the effects and the possible mechanisms of ginsenoside Rb1 on abnormal phosphorylation of Tau induced by Aβ_1-42 in the hippocampal slices.Slices were divided into model group (treated with Aβ_1-42),ginsenoside Rb1 group (treated with Aβ_1-42 and different doses of ginsenoside Rb1) and control group (treated with the same volume of vehicle).The expressions of Tau,p-Tau,Erk1/2 and p-Erk1/2 were observed by Western blot.Results showed that the expressions of p-Tau (199,202,396) and p-Erk1/2 in the model group were significantly higher than those in the control group (P<0.01).While,the expressions of p-Tau (199,202,396) and p-Erk1/2 in ginsenoside Rb1 treated groups were significantly lower than those in model group (P<0.01 or P<0.05),and ginsenoside Rb1 showed a dose-dependent reverse effects of p-Tau and p-Erk1/2 expression.The results suggested that ginsenoside Rb1 could reverse Aβ_1-42 induced hyperphosphorylation of tau and the mechanism maybe through inhibiting the activation of Erk1/2.