In the process of vegetable fermentation, the variety and quantity of microorganisms are complex and changeable. Lactic acid bacteria (LAB), as the main power in the process of vegetable fermentation, participate in the regulation of various metabolic pathways and affect the formation of flavor. In this review, the changes of major flavor metabolites during vegetable fermentation and their internal relationship with the community structure and abundance of LAB were summarized, then the potential mechanism of LAB fermentation to produce flavor substances was discussed. Moreover, the application of LAB in vegetable fermentation was prospected.