In this paper, the oligopeptides content, relative molecular weight distribution and amino acid composition in fermented soy sauce without additives (NSS) were determined and compared with commercially premium grade soy sauce (PSS) and three grade soy sauce (TSS).The results showed that the content of oligopeptides in NSS was 6.79 g/100mL, which were 2.23 fold of that in PSS and 2.30 fold of that in TSS.The bioactive oligopeptides (molecular weight 140-500) component in NSS was up to 47.47% and its content was 3.22 g/100mL, which were 2.95 fold of that in PSS and 3.03 fold of that in TSS.The essential amino acid content of NSS was 1.229 g/100 mL, which were 2.08 fold of PSS and 2.63 fold of TSS.Lysine content of NSS was 4.37 fold of PSS and 30.60 fold of TSS.This article provides a new basis for scientific evaluation of the nutrition and quality of fermented soy sauce.