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