Raw-materials based broad bean paste (rmBBP) is popular among consumers. Though high salinity can select functional microbial community for fermentation, it also impaired the fermentation efficiency of rmBBP and unfavored human health. Therefore, this study aimed to construct a synthetic microbial community based on key functional microbes for reduced salt rmBBP fermentation based on the elucidation of the microbial community succession during fermentation. Based on the tracked determination and multivariate statistical analysis of the physicochemical parameters, metabolites and the structure of microbial community, salinity and microbial interactions were key drivers for the succession of microbial community. Aspergillus, Staphylococcus, Weissella and Tetragenococcus were predicted to play key roles during fermentation. After that, core species were isolated from rmBBP mash and their salinity tolerance and metabolic characteristics were evaluated. Finally, a synthetic microbial community (Aspergillus oryzae, Staphylococcus carnosus, Tetragenococcus halophilus and Weissella confusa) was constructed and applied in reduced-salt rmBBP fermentation. The bioaugmentation contributed to the accumulation of volatile metabolites while effectively maintaining the acidity during rmBBP fermentation when salinity was reduced from 12% to 10%. In general, this study developed a synthetic microbial community with desired characteristics for successful reduced-salinity rmBBP fermentation.