Abstract: 【Objective】This paper investigated the effects of the combinations of Naian and humic acid on the growth and quality improvement of tobacco leaves, on the available cadmium(Cd) content in soil and Cd content in tobacco leaves and their correlations, which would provide technical support for the safe production of tobacco in slightly Cdcontaminated soil.【Method】Four treatments were set up as field experiments,T1:no humic acid and Naian added as control(CK), T2:Naian(1.2 g a.i/ha), T3:humic acid(750 kg/ha), T4:Naian(1.2 g a.i/ha) +humic acid(750 kg/ha).Agronomic characters of tobacco plantswere investigated after 90 d of transplanting.The yield, chemical quality and Cd content of tobacco leaves were determined after 100 d of transplanting.The available Cd content, total Cd content and pH in the soil at 5-20 cm layer were analyzed after tobacco leaves harvest.【Result】Compared with T1(CK), T2 significantly promoted the yield of tobacco leaves by 5.99% and significantly reduced nicotine by 11.92% (P< 0.05, the same below).T3 significantly promoted the yield of tobacco leaves by 7.00% and significantly increased the contents of total sugar, reducing sugar, total nitrogen and potassium in the tobacco leaves by 19.11%, 12.65%, 21.19% and 9.87%, respectively.T4 significantly promoted the yield of tobacco leaves by 14.70%, significantly increased the contents of total sugar, reducing sugar, total nitrogen and potassium in the tobacco leaves by 23.36%, 16.41%, 13.25%, 13.73%, and significantly reduced the nicotine content by 16.89%.The coordination of chemical composition of tobacco leaves was the optimal.The application of humic acid(T3 and T4) significantly reduced the contents of Cd in tobacco leaves, and reduced by 0.96 and 1.22 mg/kg compared with T1(CK), the reduction rate was 35.80%-46.51%.The enrichment coefficient of Cd in tobacco leaves decreased from 8.22 to 5.27-5.90, which effectively reduced the enrichment effect of tobacco leaves on Cd.Humic acid(T3 and T4) reduced the contents of available Cd in soil by 11.95-14.64% and increased soil pH by 0.50-0.54.The results showed that there was extremely significant positive correlation between soil available Cd content and tobacco leaf Cd content(P< 0.01), while soil pH was significantly negatively correlated with soil available Cd and tobacco leaf Cd content.【Conclusion】The combination of Naian or humic acid has obvious synergistic effects on the improvement of the growth and quality of flue-cured tobacco, and effectively reduce the accumulation of Cd in tobacco leaves.The combined application of Naian and humic acid would be an effective technology for safe production of tobacco in the tobacco planting areas in slightly Cd-contaminated soil.