In this study， we utilize the high-throughput sequencing to profile while analyzing the bacterial communities and the quality of pickles with chitosan oligosaccharides. The results have indicated that chitosan oligosaccharides can effectively reduce the nitrite content， increased the total acid and amino acid nitrogen content in pickles. When the chitosan percentage in pickles was 1%， the nitrite content of the test group was （1.08±0.39） mg/kg （50%）， the total acid was （7.42±0.25） g/kg（187%） and the amino acid nitrogen was （56.67±7.5） g/kg （132%）. The microbial community structure was obviously affected by chitosan oligosaccharides. Further analysis indicated that Firmicutes and Proteobacteria were the dominant phyla in the samples during the fermentation. Among them， a total of 17 species of microorganisms were observed as the genus during the natural fermentation group. However， only 9 species of microorganisms were observed in chitosan pickles. At the middle stage of fermentation （3 d）， the addition of chitooligosaccharide caused the dominant bacteria Exiguobacterium to be replaced by Lactococcus in the natural fermentation process. After 5 days of fermentation， Pantoea and Leuconostoc dominate the fermentation process in the naturally fermented samples， while the dominant genus in chitosan pickles is Lactococcus and continues to the end of the fermentation process. In summary， the results showed that chitosan oligosaccharide （COS） is expected to improve the growth of beneficial bacteria and the quality of pickles during the fermentation process.