The present invention provides a transdermal delivery system (for example, in the form of a patch) having a double-layer structure including a drug-containing matrix layer and an adhesive layer, wherein the drug-containing matrix layer is obtained by completely dissolving donepezil using a certain polymer and then formulating along with an adhesive； and a process for preparing the same. The transdermal delivery system according to the present invention does not show any crystallization of donepezil in the formulation, can release donepezil at a uniform rate for a long time, and can inhibit the release dumping phenomenon that occurs in a transdermal delivery system having a single-layer structure.
