Soil health and chemical fertilizer reduction are the basis for the development of green agriculture.It is of great significance for scientific fertilization to explore the effects of nitrogen reduction and biochar addition on tobacco planting soil. Taking‘K326’tobacco rhizosphere soil as the research object，the effects of biochar and nitrogen reduction measures on soil nutrients，carbon content and soil microbial community were studied by field experiment.Biochar combined with nitrogen reduction measures increased the content of available phosphorus in soil，and T3 treatment had the largest increase of 82.22%.In the four growth stages of tobacco，the available potassium content of T4 treatment was significantly increased by 11.89%，35.11%，25.95% and 15.85% compared with CK2.Compared with CK2，the content of available nitrogen increased by 7.21%，8.03%，12.41% and 12.76%，respectively.The total carbon content in the four growth stages of T3 treatment was significantly increased by 12.44%，18.48%，16.58% and 6.15% compared with that of CK2.The combination of biochar and nitrogen reduction measures could increase the soil C/N ratio，with the maximum of 8.96 in T4 treatment.Actinobacteria，Gammaproteobacteria and Alphaproteobacteria were the dominant bacteria in tobacco growing soil.The dominant fungi were Sordariomycetes，Eurotiomycetes and norank_p_Ascomycota.Compared with CK2 treatment，the combination of biochar and nitrogen reduction measures increased the relative aboundance of Alphaproteobacteria，Ktedonobacteria，Euromycetes and norank_p_Ascomycota， decreased the relative abundance of Actinobacteria and Acidobacteria.The results showed that the combination of biochar and nitrogen reduction measures could significantly increase the ratio of soil carbon and nitrogen in crop rhizosphere，improve the micro ecological environment of tobacco planting soil，increase the relative abundance of soil functional microorganisms，and improve the nutrient utilization efficiency，which provided a theoretical basis for the efficient use of nitrogen fertilizer in tobacco planting soil and the cultivation of healthy soil.