Neurodegenerative diseases including Alzheimer's, Parkinson's, and type II diabetes are recognized to be related to proteins misfolding into amyloid fibrils and other aggregates with a β-sheet conformation. Herein, self-assembled peptide micro/nanoarchitectures were designed and prepared to mimic those aggregates. A short β-amyloid peptide derivative with a diphenylalanine moiety was synthesized, which could self-assemble into nanofibers via β-sheet conformation in an aqueous solution with a concentration of 1 mg mL-1 at pH about 8. By adjusting the pH to around 6.5, a peptide solution with a concentration of 15 mg mL-1 could change to a supramolecular hydrogel. The influence of self-assembly conditions including peptide concentration, temperature, pressure, and self-assembly time were investigated in detail. It was found that the self-assembled nanofibers could further aggregate into catenulate microfibers in solution as well as layer-by-layer plaques in the hydrogel under particular conditions.