To enhance the stability and controllability of Honggu Huangjiu production, a liquid Honggu Huangjiu starter based on a synthetic microbial community was developed. 12 core microorganisms were screened from commercially available solid Huangjiu starters. A synthetic microbial community consisting of Clavispora lusitaniae, Aspergillus niger, Monascus purpureus, and Rhizopus arrhizus was optimized through Plackett-Burman experiment. The four strains were compounded at a 1∶1∶1∶1 ratio of microbial concentrations, and liquid Huangjiu starter (YT) was prepared using gelatinized wheat as the substrate. Using Nanyang Honggu as the raw material and liquid starter for Huangjiu fermentation, the resulting product (CY) complied with the national standard for Huangjiu. Compared with most Huangjiu brewed with solid-state starter, CY had significantly higher contents of total acids and total sugars, while there was no significant difference in pH value between CY and Huangjiu brewed with traditional Huangjiu starter. The contents of amino acid nitrogen [(0.62±0.02) g/L], non-sugar solids [(35.51±0.48) g/L], and alcohol degree of CY were lower than those of Huangjiu brewed with solid-state Huangjiu starter. Further research on the flavor compounds of CY showed that nine characteristic flavor substances of Huangjiu were detected, including ethyl caprate, phenethyl acetate, ethyl caprylate, diethyl succinate, ethyl nonanoate, ethyl laurate, isoamyl alcohol, ethanol, and phenethyl alcohol. Compared with traditional solid-state starter Huangjiu, CY exhibited higher relative contents of key aroma components such as n-nonanal, diethyl succinate, phenethyl alcohol, and ethyl caprylate. It was demonstrated that Honggu Huangjiu brewed with liquid Huangjiu starter based on a synthetic microbial community showed excellent performance in both physicochemical properties and flavor composition. It was hoped that this research could provide technical references for the standardized production of Honggu Huangjiu. 〖