Amyloid plaques are one of the hallmarks of Alzheimer's disease (AD). The lack of specific probes that can detect individual senile plaques in AD has prompted the development of magnetic resonance imaging (MRI) probes. In this study, based on DTPA-gadolinium (III) and congo red (CR), a novel specific MRI probe precursor CR-BSA-(Gd-DTPA)n was successfully synthesized. Its ability to bind to amyloid plaques was evaluated by brain sections from APP/PS1 transgenic mice. Its specificity for Aβ plaques was further demonstrated by immunohistochemistry (IHC) staining with the monoclonal antibody to the Aβ protein. Meanwhile, the amyloid deposits detected by the CR-BSA-(Gd-DTPA)n were matched to the amyloid deposits detected by Aβ specific antibody. We also found that a few amyloid-like deposits which was not detected by IHC. The findings indicated that the probe perhaps could detect the neurofibrillary tangles (NFT) similar to the effect of CR itself, and this will be verified in future experiments. The works suggested that the Aβ protein-specific magnetic resonance contrast agent precursor CR-BSA-(Gd-DTPA)n can be used as a potential fluorescence and MR multi-modal imaging probe precursor to display individual senile plaques in AD.