To study the effect of lime nitrogen application on rhizosphere soil microflora of tobacco plant and its incidence of tobacco bacterial wilt，root soil was collected for 16S/18S rDNA gene sequencing at different growing stages of tobacco plants to analyze the changes of microbial quantity，diversity and community structure during the growth of tobacco plants. Results showed that after the application of lime nitrogen，in the rosette stage of tobacco plant growth，the relative abundance of Nitrospirae and Basidiomycota increased by 55.0% and 105.6%，respectively，and the Ascomycota decreased by 20.2%，the most vigorous bacteria Sobs index，Shannon index and Chao index increased by 6.3%，3.1% and 3.4%，respectively.PCA analysis showed that the microbial flora structure of rhizosphere soil treated with lime nitrogen was different from that of the control group from the beginning of the rosette stage，and the difference gradually increased with the growth of tobacco plants.The analysis of species differences showed that the abundance of functional bacteria related to soil nitrogen cycle，such as Sphingomonas，Nitrospira，Flavisolibacte，etc.，was significantly increased in the treatment with lime nitrogen.Statistics on the incidence of bacterial wilt and tobacco yield in the mature period showed that the control rate of lime nitrogen treatment on tobacco bacterial wilt reached 49.9% and the tobacco yield increased by 11.7%.