Abstract: To effectively improve the ability of nitrogen uptake and to decrease the loss of nitrogen in a tobacco field, the effects of a composite soil conditioner consisting of an organic fertilizer, bentonite and humic acid (HA)on NH₄⁺-N adsorption properties of yellow soil were studied with a soil culture experiment and an isothermal adsorption experiment. The results showed that in this experiment, the effects of soil conditioner on NH₄⁺-N uptake enhanced gradually with the proceeding of culture time and peaked at 546.34 mg/kg on the 60th day. The isothermal adsorption curves of NH₄⁺-N in different treatments could be well fitted by Langmuir equation. With the increase of soil conditioner rate, the maximum adsorption capacity(Q_max)of soil for NH₄⁺-N raised. The ratio of humic acid in soil conditioner influenced the adsorption of yellow soil for NH₄⁺-N. When the ratio of humic acid in soil conditioner was 20%, the capacity and intensity index of NH₄⁺-N adsorption of yellow soil increased significantly. For flue-cured tobacco production, the mixture of organic fertilizer, bentonite and humic acid at a ratio of 6:2:2 could be used as soil conditioner, and its application amount should be determined according to the soil fertility of tobacco fields. In conclusion, the composite soil conditioner consisting of organic fertilizer, bentonite and humic acid can effectively regulate the nitrogen content and intensity index of yellow soil and significantly increase the content of NH₄⁺-N in yellow soil, which ensures the nitrogen need of flue-cured tobacco at early growing stage and reduces the environment risk of nitrogen.