Strong-flavor Baijiu is one of the important types of Chinese liquor. The ethyl caproate is the characteristic flavor compound in strong-flavor Baijiu. The precursor caproic acid required for the synthesis of ethyl caproate mainly relies on the metabolism of caproic acid-producing bacteria （CPBs） during the process of fermentation. Studies on the isolation， identification and metabolic functions of CPBs have become one of the hotspots in improving the quality of Baijiu. This article reviewed the isolation of CPBs from pit mud. Three types of CPBs commonly used in the fermentation system of strong-flavor Baijiu and the pathway of synthesizing caproic acid were introduced. The effects of pH and the composition of substrate on the yield of caproic acid were discussed. The impacts of other microorganisms in the microbial community on CPBs were introduced as well. It will provide a theoretical basis for improving the quality of strong-flavor by investigating the mechanism and affecting factors of producing caproic acid driven by microorganisms in the fermentation system of strong-flavor Baijiu.