Abstract: 【Objective】 The aim of this study was to investigate the differences of soil bacterial community structure and diversity among 4 forages species in fodder-crop rotation mode, and to clarify the diversity structure and dynamic characteristics of soil bacteria in this area.【Method】 Firstly, bacterial DNA was extracted from the rhizosphere soil of four kinds of forages, then DNA was quantified and sequenced by Nanodrop, last but not least, the biological information of soil bacteria was analyzed after sequencing.【Result】 The results showed that the composition of soil microbial community of the four forages was relatively stable, and the bacterial diversity and community structure were significant differences in different periods or seasons. The diversity and richness of soil microbial community of black oat-potato rotation mode were significantly higher than those of the other three forages, and the soil biological activity was significantly improved.【Conclusion】 The bacterial community diversity in soil of black oat-potato rotation mode was significantly higher than that of other modes of potato with oats,Vicia sativa and Vicia villosa,which would be beneficial to maintain the diversity and richness of soil microorganisms and to improve the rate and efficiency of land utilization.