In this research, we aimed to 1) develop a point-of-care lateral flow biosensor for detecting plasma amyloid-β based on antigen-antibody interaction and 2) quantitate the amyloid-β bound on the membrane by high sensitivity quantitative analysis using digital camera and image processing program. The biosensor is a simple designed tool but highly effective for the on-site quantitative analysis that we will be able to provide the information of risk of having AD before entering the stage that cannot be cured.