Abstract: Five kinds of different varieties and maturity Euryale ferox seeds samples were selected and their protein subunit structures and amino acid compositions were analyzed in the article. The results showed that the protein content of northern Euryale ferox ( mature) seeds was higher markedly than southern Euryale ferox ( mature) seeds ( p ≤ 0.05) , furthermore the essential amino acids、sweet amino acids and umami amino acids contents in northern Euryale ferox ( mature) seed proteins were also higher than southern Euryale ferox ( mature) seeds, which illustrated that the northern Euryale ferox was better than the southern Euryale ferox in terms of ( nutrition and taste. It was resulted that in the SDS-PAGE analysis, twenty bands were separated from the total Euryale ferox seeds protein with relative molecular mass between 16.24 ~ 82.04 kDa. In addition, the subunit with relative molecular mass at about 35.9 kDa had highest content which was the major subunit in total Euryale ferox seeds protein.The contents of water soluble protein were few in Euryale ferox seeds and there were great differences between different maturites.No water soluble protein was detected in the Euryale ferox seeds from southern Euryale ferox ( not mature) and Huainan Euryale ferox ( not mature) .The alcohol soluble protein subunit compositions had great diversities among different varieties but no much difference was found in the subunits and molecular weight distribution of alkali-soluble protein from different breeds and ripeness.