This study is intended to examine the tDCS and Morris Water maze training in Alzheimer’s disease(AD) rats on Tau protein expression. Experiment groups were divided into four groups and assigned 16 rats to each group. Group Ⅰ was a control group(AD induced by scopolamine); Group Ⅱ was a experimental control group(AD injured by scopolamine and treatment tacrine); Group Ⅲ was a group of tDCS application after AD injured by scopolamine; Group Ⅳ was a group of morris water maze training after AD injured by scopolamine. In cognition test, the outcome of group Ⅱ was significantly lower than the groups(p<.001). and group Ⅲ, Ⅳ were significantly low result at 14 days(p<.05). In histological finding, the experimental groups were destroy of micro vessels and finding of cell atropy and swelling. Group Ⅲ, Ⅳ were decreased in degeneration of liver and kidney cells. In immuno- histochemistric response of BDNF and tau protein in hippocampus, BDNF expression of Group Ⅱ was more increase than the other groups. and increase of BDNF expression was Ⅲ, Ⅳ were higher than group Ⅰ at 21 days. Tau protein expression of Group Ⅱ was more decrease than the other groups. and decrease of Tau protein expression was Ⅲ, Ⅳ were lower than group Ⅰ at 21 days. These result suggest that improved tDCS and morris water maze training after scopolamine induced is associated with dynamically altered expression of BDNF and Tau protein in hippocampus and that is related with cognitive function.