The present invention relates to a transdermal composition for dementia treatment containing donepezil as an active ingredient. The transdermal composition according to the present invention contains highly concentrated donepezil in a hydrophobic matrix, can continuously release the drug for a long time by having excellent long-term adhesion to the skin, and further exhibits consistently effective therapeutic effects over a long period of time by having a significantly improved skin penetration rate in comparison with conventional donepezil patches.