The abnormal assembly of beta-amyloid (Ab) peptides into neurotoxic, beta-sheet-rich amyloid aggregates is a major pathological hallmark of Alzheimer's disease (AD). Light-induced photosensitizing molecules can regulate A beta amyloidogenesis. Multiple photochemical analyses using circular dichroism, atomic force microscopy, dot blot, and native gel electrophoresis verified that photoactivated meso-tetra(4-sulfonatophenyl)porphyrin (TPPS with M = 2H(+), Zn2+, Cu2+, Mn2+) successfully inhibits A beta aggregation in vitro. Furthermore, A beta toxicity was relieved in the photoexcited-TPP-Streated Drosophila AD model. TPPS suppresses neural cell death, synaptic toxicity, and behavioral defects in the Drosophila AD model under blue light illumination. Behavioral phenotypes, including larval locomotion defect and short lifespan caused by A beta overexpression, were also rescued by blue light-excited TPPS.