The present invention relates to an immunoadjuvant composition that includes amphiphilic polymer particles in an oil-in-water emulsion state containing an amphiphilic poly-amino acid polymer and a method of preparing the same. Since the immunoadjuvant composition of the present invention is prepared using an amphiphilic poly-amino acid polymer, it allows the provision of a vaccine immunoadjuvant composition which is more biocompatible and has a high antibody titer.
