To explore the effects of high-carbon basal application on the functional diversity of microbial communities in tobacco-plantingsoil,field trials were conducted to study the effects of different high-carbon basalrates(0,0.9,1.5 and 1.8 t/hm2)on the growth and development of tobacco plants. The physical and chemical properties of soil and the quality of roasted tobacco leaves were analyzed. Biolog-ECO method was used to analyze the diversity of soil microbial carbonmetabolism. The results showedthat:(1)0.9～ 1.5 t/hm2 high-carbon base fertilizer significantly promoted the plantheight,stem circumference,maximum leaf area,and root dry weight of flue-cured tobacco,and the effect of application of 1.8 t/hm2was significantlyreduced；(2)Compared with thecontrol,the application of high-carbon basal fertilizer reduced thesoil moisture content,increased the soil pH value and the ratio of microbial biomass carbon tonitrogen；(3)Biologe-ECO analysis showed that the AWCD value and diversity index of soil microorganisms were the highest with the application of high-carbon basal fertilizer 1.5 t/hm2,and the soil microbial utilization rates of aminoacids,polymers,carbohydrates,and carboxylic acids were also significantly increased. The principal component analysis showed that the application of high-carbonbasal fertilizer significantly changed the microbial community structure in thesoil,and the microbial carbon metabolism diversity score was the highest under the treatment of high-carbon base fertilizer with 1.5 t/hm2；(4)The application of high-carbon base fertilizer improved the chemical quality of cured tobacco leaves. The best treatment effect was 1.5 t/hm2. Thecontents of totalsugar,reducing sugar and potassium increased by22.81%,35.72% and 25.61% respectively compared withthe control. Takentogether,the optimum application rate of high-carbon basal fertilizer in Xuchang tobacco area is 1.5 t/hm2.