Abstract: 【Objective】 To explore the effects of different nitrogen application levels on rhizosphere soil physicochemical properties，bacterial community structure and diversity，which couldprovide reference for rational application of nitrogen fertilizer in flue-cured tobacco. 【Method】 Tobacco varietyYunyan 100 was used as experiment material. Five treatments with different nitrogen application were set up，including no nitrogen application（N0，0 kg/ha），conventional nitrogen reduction of 45.0%（N1，55 kg/ha），conventional nitrogen reduction of 22.5%（N2，78 kg/ha），conventional nitrogen application（N3，101 kg/ha），and conventional nitrogen increase of 22.5%（N4，124 kg/ha）. During the maturity period，the rhizosphere soil samples were collected to study the differencesof physicochemical properties，the bacterial community diversity and structural composition in different treatments. 【Result】 Compared with the N0 treatment，the nitrogen application treatment greatly increased the contents of alkali-hydrolyzed nitrogen，available phosphorus，available potassium，water-soluble chlorine，available boron and available zinc，except for a slight decrease in organic matter content. In addition，the treatment of N2-N4 was beneficial to increase the activities of soil cellulase，sucrase and urease，and reduce the activity of acid phosphatase. The results of correlation analysis indicated that the activity of soil cellulase was extremely significantly and positively correlated with the contents of available phosphorus，available potassium and available boron in the soil（P<0.01，the same below）. Soil urease activity was extremely significantly and negatively correlated with soil pH and organic matter content，while it was significantly and positively correlated with alkali-hydrolyzed nitrogen，available boron and water-soluble chlorine contents（P<0.05，the same below）. The activity of soil acid phosphatase was extremely significantly and significantly negatively correlated with soil pH and available phosphorus content respectively. There was no significant difference in the Alpha diversity index of the rhizosphere soil bacterial community among different nitrogen application treatments（P>0.05），but there were significant differences in the bacterial community structure. Proteobacteria，Actinobacteria，Chloroflexi and Acidobacteria were the main dominant bacterial phyla in the rhizosphere soil bacterial community. Nitrogen application has increased the relative abundance of Proteobacteria and Acidobacteria in the rhizosphere soil. With the increase of nitrogen application level，the relative abundances of Gaiella， Nitrospira and Agromyces showed a changing trend of first increasing and then decreasing. Nitrogen application treatment reduced the relative abundances of Sphingomonas and Paenibacillus. The results of redundancy analysis indicated that the soil bacterial community was mainly affected by soil pH，the contents of alkali-hydrolyzed nitrogen，available zinc， water-soluble chlorine，as well as activities of cellulase，urease and acid phosphatase. 【Conclusion】 There are differences in the effects of different nitrogen application rates on the rhizosphere soil physicochemical properties and bacterial community in flue-cured tobacco. Reasonable nitrogen application（78 kg/ha）can increase soil cellulase and sucrase activities，and improve soil bacterial community structure. Meanwhile，soil pH，alkali-hydrolyzed nitrogen，available zinc， water-soluble chlorine content，cellulase，urease，and acid phosphatase activities are the key factors influencing rhizosphere soil bacterial communities.