To systematically analyze and evaluate amino acids of dried osmund, 17 kinds of amino acids were derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate and then were analyzed by ultra performance liquid chromatography. L-tryptophan was quantitatively analyzed by ultraviolet spectrophotometric. Nutritional value evaluation of dried osmund protein was synthetically studied by methods of ratio coefficient of amino acid and fuzzy discernment. The results showed that the sample had 18 kinds of amino acids. The content of the total amino acids was up to 697.93 mg/g protein.The proportion of essential amino acids in total amino acids was 0.45, and the proportion of essential amino acids in non-essential amino acids was 0.83, which was higher than that of FAO/WHO pattern recommended. The content of crude protein was 12.09%. The contents of flavor amino acids、sweet amino acids, aromatic amino acids and medical amino acids were 23.99%, 22.16%, 12.46% and 63.97% respectively. All kinds of human essential amino acids kept such a balanced proportion that they were close to the FAO/WHO standard pattern. Among all human essential amino acids, the first limited amino acid was isoleucine.