Abstract: To investigate the effects on growth and intestinal microbiota of largemouth bass（Micropterus salmoides） in bass-crab polyculture pattern, the frozen fish, formulated feed and frozen fish plus formulated feed（mixed） were used with 16 S rRNA high throughput sequencing. Results showed that the formulated feed group had the lowest average final body weight, body length, and specific growth rate, which were significantly lower than that of the frozen fish group and the mixed group（P＜0.05）, but there were no significant differences between the frozen fish group and the mixed group（P＞0.05）. The community richness and diversity of the intestinal bacterial community were the lowest in the formulated feed group, and the highest in the frozen fish group. In the genera level, Klebsiella, Mycobacterium, Romboutsia and Photobacterium were the dominant gene-ra in the frozen fish group, while Romboutsia, Klebsiella, Mycobacterium and Cetobacterium were the dominant genera in the formulated feed group, and Klebsiella, My-cobacterium, Mycoplasma and Candidatus＿Brocadia were the dominant genera in the mixed group respectively. Functional prediction showed that the abundance of functional genes involved in "energy production and conversion" and "coenzyme transport and metabolism" were dominant in the frozen fish group. Meanwhile, the abundance of functional genes involved in "amino acid transport and metabolism" "li-pid transport and metabolism" "translation, ribosomal structure and biogenesis" and "transcription" were dominant in the formulated feed group. However, there was no significant difference in the abundance of functional clusters among the three groups（P＞0.05）. Taken together, the formulated feed sharped the structure of intestinal microflora to a certain extent and decreased the diversity of bacterial communities obviously. The present study provided scientific data for healthy cultivation and formulated feed innovation of Micropterus salmoides.