The invention discloses a method for detecting donepezil in a Chinese patent medicine and health-care food through liquid chromatography-mass spectrometry. The method comprises the following steps of(1) preparing a reference substance solution: adopting a donepezil reference substance and methyl alcohol to be prepared into the reference substance solution; (2) preparing a to-be-tested sample solution: extracting a traditional Chinese medicine preparation and health-care food for assisting memory improvement through the methyl alcohol, and purifying the extracted solution to obtain the to-be-tested sample solution; (3) feeding the reference substance solution and the to-be-tested sample solution in a liquid chromatograph/mass spectrometer, and qualitatively and quantitatively determining the donepezil in a testing product solution. The method provided by the invention adopts a multiple-reaction monitoring manner for detecting, and is low in interference, high in sensitivity, and accurate in detection result.