[Background] Highland barley Baijiu is a product of multispecies solid-state fermentation. It is important to regulate the fermentation of highland barley Baijiu through analyzing the important functional microbiota and their metabolic characteristics. [Objective] The purpose of this study was to reveal the flavor-related microbiota during highland barley Baijiu fermentation and resolve their co-metabolism. [Methods] the diversity and composition of microbial community during highland barley Baijiu fermentation were revealed by high-throughput sequencing. the flavors of fermented grains were detected by HS-SPME-GC-MS. Then flavor-related microbiota during highland barley Baijiu fermentation was revealed by correlation analysis between microbes and flavors. The effect of physical and chemical factors to the flavor-related microbiota was revealed by the Mantel test. the simulated fermentation with six strains under laboratory conditions was carried out to resolve their co-metabolism. [Results] nine dominant fungus and eight dominant bacteria (relative abundance>1%) were found during highland barley Baijiu fermentation. Aspergillus, Komagataella, Lactobacillus, Pichia, Saccharomyces and Weissella were identified as flavor-related microbiota. Reducing sugar (r2=0.946 9, P=0.013 2) and acidity (r2=0.847 6, P=0.048 6) were determined as key factors driving the succession of the flavor-related microbiota. The simulated fermentation with six strains revealed the in vitro system had the same microbial succession and flavors structure as the in situ system. [Conclusion] This work revealed the flavor-related microbiota and key factors driving their succession, and verified the metabolic characteristics of flavor-related microbiota by simulated fermentation. These results might provide a new perspective for regulating flavors information during highland barley Baijiu fermentation.