We prepared innovative polyelectrolyte complex nanoparticles(AAP/LCS NPs), formed by mixing negatively charged auricularia auricular polysaccharide(AAP) with positively charged low molecular weight chitosan(LCS) in the aqueous medium.The AAP was extracted and purified from auricularia auricular, and then characterized by micrOTOF-Q mass spectrometer, UV/Vis spectrophotometer, moisture analyzer and SEM.