Abstract: Field experiment was carried out to study the effect of different organic materials on soil carbon and nitrogen and C/N, sensor quality of flue-cured tobacco. Results showed that rotten wheat straw, green manure and green manure with microbial agents could increase microbial quotient and antecedent soil organic carbon, total nitrogen, microbial biomass C, microbial biomass N, with microbial biomass C/N averaged at about 5. The analysis of tobacco quality showed that tobacco leaf C/N increased slowly before 60d after transplanting then entered the period of rapid growth. Leaf C/N decreased after flue-curing and the sensory quality of flue-cured tobacco was improved. Correlation analysis showed that soil carbon and nitrogen content had significant or extremely significant positive correlations with total score of sensory quality. Tobacco leaf C/N had no linear correlation with total score of sensory quality, but had negative correlations with the aroma, pungent, aftertaste and momentum, had positive correlations with quality and concentration of aroma. Green manure with microbial agents rendered the best effect.