Abstract: The content of amino acids was detected in 5 fruit mulberry varieties coming from Yu mai County in Xinjiang,Aktao. The amino acids composition,total amino acids,essential amino acids,amino acids with flavor enhancement effect,amino acids with medicinal function and branched-chain amino acids among different varieties were compared and amino acid evaluation index(RAA,RC and SRC)was adopted to make comprehensive nutritional evaluation.The results showed that 16 kinds of amino acid were detected in 5 mature mulberry,with the total content ranging from 0.802 to 1.323 g/100 g and with the highest content of glutamate and the lowest content of tryptophan and methionine. There was no significant difference in EAA/TAA among different varieties(P>0.05).The content of total amino acids,essential amino acids,amino acids with flavor enhancement effect,amino acids with medicinal function and Branched-chain amino acids of 8632 were significantly higher than those of other varieties,followed by Hongguo no.2. The essential amino acids were conformed to or close to FAO/WHO amino acid model,except methionine+cystine. Methionine+cystine were the first limiting amino acid in mulberry fruit by amino acid ratio coefficient method. The SRC score order of different varieties was Hongguo no.2> 8632>Taiguo> Da 10>Guoxuan no.2,and SRC scores of Hongguo no.2 and 8632 were 84.563 and 82.859 respectively,which higher than those of other varieties. The results showed that the amino acid nutritional value of 8632 and Hongguo no.2 was higher among the five fruit mulberry varieties,which had obvious advantages as the fruit mulberry varieties popularized in Xinjiang.