Provided is a recombinant P particle formed from a norovirus capsid P protein of a chimeric Aβ1-m peptide (m being an integer ranging from 6 to 15), wherein the recombinant P particles form an ordered and repetitive antigen array. Also provided are a nucleotide sequence encoding the recombinant P particle, a pharmaceutical composition comprising same and a use thereof for preparing a medicament for treating or preventing Alzheimers disease. Also provided is a method for preparing the recombinant P particle.