Abstract: The present application relates to the molecular labeling and in vivo imaging of amyloids. Specifically, the present application relates to a polypeptide-based method/vector for targeting amyloids. Such a method/vector enables the transportation of compounds or drugs across blood-brain-barrier of an individual and then binding to amyloids in brain. Particularly, the vector of the present application can transport an imaging group linked to the vector across the blood-brain-barrier, and can binds to amyloids in brain, and thus enables the labeling and imaging of amyloid deposits. When used as an imaging agent for detecting amyloid deposits in body or tissues, the vector may be labeled with suitable optical imaging groups, radioactive isotopes or imaging groups suitable for MRI or CT detection.