The abnormal aggregation of amyloid-beta (Aβ) has been widely believed to play an important role in the pathogenesis of Alzheimer’s disease (AD), which is also recognized as one of the main biomarkers for AD diagnosis. The peptide sequence Lys-Leu-Val-Phe-Phe (KLVFF) is considered as the main driver of the fibrillation of Aβ, which also can be utilized to target Aβ and inhibit its aggregation. In this study, KLVFF and Fmoc-KLVFF fluorescent nanoparticles were self-assembled through zinc coordination and π-π stacking. The recognition of Aβ aggregates including oligomers and fibrils by fluorescent nanoparticles can be realized through aromatic, hydrophobic, and hydrogen-bond interactions. The fluorescent nanoprobes can distinguish Aβ aggregation formats and detect Aβ at the limit of 1 pg/mL (S/N = 3). Hence, the detection of Aβ aggregates by fluorescent peptide nanoparticles has great potential for AD diagnosis and progression prediction.