In this study， the changes in microbial diversity during natural fermentation of red cabbage at different salt concentration levels (1%， 3%， 5% and 10%) were investigated by using 16S rRNA amplicon sequencing technology， and the changes in physicochemical properties during natural fermentation of red cabbage were determined， as well as the sensory evaluation of naturally fermented red cabbage at different salt concentrations was also carried out. The results showed that the red cabbage naturally fermented under different salt concentrations was dominated by Proteobacteria and Firmicutes， and the main genera are Lactobacillus， Enterobacter， and Lactococcus， Leuconostoc， Serratia， Weissella， etc. In addition， different salt concentrations had significant effects on the physicochemical properties of fermented red cabbage such as pH value， total acid， reducing sugars and nitrite， among which the fermented red cabbage at 3% salt concentration had the highest accumulation of total acid， faster consumption rate of reducing sugars and relatively faster decrease rate of nitrite. The correlation results showed that Lactobacillus， Enterobacter， Lactococcus， Weissella， Streptococcus， Akkermansia and pH value， total acid， reducing sugar， nitrite and other physical and chemical properties were highly correlated. According to the sensory evaluation， it was concluded that naturally fermented red cabbage samples at 3% salt concentration had the best taste， followed by 1% and 5% salt concentration， and 10% salt concentration had poor taste. Therefore， red cabbage samples naturally fermented at 3% salt concentration had higher microbial diversity abundance， highest accumulation of total acid， and better taste and flavor， which was more suitable for the fermentation of red cabbage.