To gain starter culture for laying the foundation for standardization of Dandouchi production technology,the predominant strains which had strong ability to decompose protein in naturally fermented Dandouchi were identified by morphological,physiological and biochemical methods,16S rDNA sequence alignment and phylogenetic tree construction firstly.Then amino acid nitrogen(AAN),trichloroacetic acid soluble protein(TCASP) and peptide molecular weight distribution(PMWD) of Dandouchi made by above strains were determined.Results showed that there were two kinds of predominant strains with different colonial morphology and strong ability to decompose protein in naturally fermented Dandouchi.They,named as DANDC1 and DANDC2,both belonged to Bacillus subtilis.The content of AAN,TCASP and peptides which molecular weight were 5 000～2 000 u,2 000～1 000 u and 1 000～500 u of Dandouchi made by starter culture were significantly higher than those of autoclaved soybean.Fermentation by different strains also significantly affected AAN and TCASP content and PMWD of Dandouchi.