Abstract: This work is to analyze the dynamic variation of microbial community during the fermentation of traditional soybean paste in northeastern China. Selecting the fermented 0 d，35 d，65 d，75 d and 105 d soybean pastes as research materials，the microbial diversity was analyzed，and the changes of proteins and amino acid-nitrogen were detected，by PCR-DGGE technique. The results showed that the dominant bacteria during the fermentation of soybean paste were Bacillus and Lactobacteria，and the Bacillus mainly covered the closely related species of B. subtilis，B. pumilus，B. amyloliquefaciens，B. licheniformis，et al. The main species of Lactobacteria included the closely related ones of Lactococcus，Leuconostoc，Weissella cibaria，et al. The dominant fungi during the fermentation of soybean paste were the closely related species of Aspergillus oryzae，Eurotium rubrum，and Aspergillus chevalieri，and they decreased gradually with the fermentation time. The crude protein of the soybean paste finally decreased to 24.76% after increasing smoothly in former fermentation process. The amino acid-nitrogen kept on increasing during whole progress and its concentration was up to 101.2 g/kg in final soybean paste.

Key words: PCR-DGGE, traditional fermented soybean paste, microbial diversity