Differences between two paddy soils, high and low in soil fertility in the red soil region were explored in content of mineral N (NH₄⁺ and NO₃^-1) and nitrification intensity at the root surface and rhizosphere of rice and in the bulk soil, as well as in growth and N accumulation of rice seedlings at 40, 50 and 60 d after sowing. Results show that soil fertility had no significant effect on NH₄⁺-N content at the root surface and rhizosphere of rice, while high fertility significantly increased NH₄⁺-N content in the bulk soil, and NO₃^-1-N contents and nitrification intensity at the root surface and rhizosphere of rice and in the bulk soil, as well. The highest nitrification intensity was observed at 2 mm away from the root surface in both soils, being 0.20 and 0.31 μmol kg^-1 h^-1 in the low and high fertility soils, respectively. Nitrification intensity in the bulk soil decreased with the increasing distance from the root surface, and approximated to the background value at 10 ~ 40 mm and 20 ~ 40 mm away from the root surface in the low and high fertility soils, respectively. Rice planting significantly enhanced nitrification intensity in the rhizosphere of the plant as compared with CK (rice plant free). High fertility improved the growth of rice significantly, especially rice root growth and aerenchyma formation and increased N accumulation in the plant. The difference in soil fertility of paddy field might cause differences in rhizospheric nitrification intensity and rice NO₃^-1absorption, which might lead to stronger rice growth potential and N accumulation ability of the plant in the soil high in fertility. Hence, appropriate increasing soil fertility of red soil paddy fields is of great significance to improving nitrification in rhizosphere of the plants and rice N nutrition in the red soil regions of subtropical China.