Abstract: In order to determine the effects of biochar on nutrition regulation of flue-cured tobacco, uptake and accumulation of nitrogen, phosphorus and potassium in flue-cured tobacco with mixed application of rice straw biochar and chemical fertilizers was studied through field experiments. The results showed that nitrogen and potassium contents in root showed a decreasing trend with the increasing amount of biochar at the resettling stage of flue-cured tobacco, but the phosphorus content in root had little change. Nitrogen and potassium contents in root, stem and leaf of flue-cured tobacco were the highest with biochar application amount of 3000 kg/ha at the topping stage. Biochar could also increase phosphorus content in roots of flue-cured tobacco at the topping stage, but phosphorus contents in stem and leaf were decreased. Phosphorus content in stem and leaf of flue-cured tobacco were the lowest with biochar application amount of 3000 kg/ha at the topping stage. The accumulation amount of nitrogen in root decreased with the increasing application amount of biochar. The accumulation of nitrogen in stem and leaf with biochar application amount of 3000 kg/ha was the highest. The accumulation of phosphorus in root, stem and leaf decreased with the application of biochar, but the accumulation of potassium increased. The accumulation of potassium in tobacco plant showed an increasing trend with the increasing application amount of biochar. In conclusion, the mixed application of biochar and chemical fertilizers could promote the absorption and utilization of nitrogen and potassium in flue-cured tobacco, but the accumulation of phosphorus was decreased.