【Objective】A large number of studies have found that changing from dry to wet significantly affects soil microbial communities and greenhouse gas emissions. However, the transient dynamic of active microorganisms and greenhouse gas emissions of soils under dry to wet fluctuations are still unclear. 【Method】In this study, the dynamic of bacterial communities and greenhouse gas emissions under dry, wet, and dry-wet changes conditions in paddy soil were investigated. The diversity, assembly, and potential functions of active bacterial communities under dry-wet change conditions were further revealed by combining ¹⁸O-based DNA stable isotope probing technology (DNA-SIP) and high-throughput sequencing. 【Result】Dry-wet change treatment significantly promoted emissions of carbon dioxide and contained significantly higher relative abundances of Actinobacteria and planctomycetes compared with those in the dry and/or wet treatments. The relative abundances of Proteobacteria, Actinobacteria, and planctomycetes increased significantly along with the incubation. DNA-SIP experiment showed that the alpha diversity of active bacteria in the dry-wet change treatment decreased significantly along with the incubation. Proteobacteria and Actinobacteria dominated the active bacterial communities, and the relative abundance of Myxococcales in Proteobacteria increased significantly along with the incubation. The assembly of active bacteria was dominated by determinism, and the contribution of determinism was increased along with the incubation. Functional prediction of active bacteria further found that carbohydrate metabolic potential decreased significantly during the incubation. 【Conclusion】In conclusion, the dry-wet change treatment significantly changed the soil bacterial community and promoted carbon dioxide emission in paddy soil. The active bacteria in the dry-wet change treatment were dominated by Proteobacteria and Actinobacteria, and their assembly was dominated by a deterministic process.