Objective:To study the effect of Xiaoyao Powder on Alzheimer's disease in hippocampal CA 3βregion of rats PP-2A,GSK-3βexpression.Methods:Rats were randomly divided into four groups , including model group, western medicine group,Chi-nese medicine group were treated with intraperitoneal injection of D-gal and A-β1-42 peptide bilateral hippocampal injection mold-ing, physiological group only with equal volume of sterile saline intraperitoneal and hippocampal injection molding .The model was completed, normal group, model group were perfused with saline , western medicine group and Chinese medicine group were treated with oxiracetam solution and Xiaoyao decoction , four groups of intragastric volume was 0.5 ml/100 g, 1 time a day, continuous 28 d. After intragastric administration of isolated rat brain immediately , packet marking in 4℃4%glutaraldehyde solution of glass container , stored at 4℃.Repair piece, cut from the hippocampus, embedded in paraffin, sliced.Dilution of PP-2A for 1∶200, GSK-3βdilution of 1∶150.Images were analyzed by using Image-pro Plus 5 image analysis system, data were conducted by SPSS11.5 statistical analysis software, the comparison between 4 groups by single factor analysis of variance , between the two two groups was compared by LSD-t test, the test level of α=0.05.Results:The expression of PP-2A positive cell number and the positive area , average optical density, integral optical density index , in Xiaoyao Powder orally intervention compared with the model group increased significantly (P<0.01);GSK-3βabove indices were significantly decreased than that in model group after Xiaoyao Powder after intragastric ad -ministration (P<0.01).Conclusion:Xiaoyao Powder can up regulate the expression of PP-2A and down regulate expression of GSK-3β, may be condensed A-β1-42 peptide induced hyperphosphorylation of Tau has certain inhibition .