Two different Indica cultivars, Zhong Han 22 (ZH, high yield) and He Sheng 10 (HS, low yield) popularly planted in red paddy soil were used to study nitrogen (N) nutritional characteristics using a rhizobox with three compartments and a soil\|slicing method. Rice plant biomass, N accumulation, N use efficiency (NUE), porosity of root (POR), rhizosphere mineral N concentration and nitrification activity were determined at 40, 50 and 60 d after sowing. The results obtained were showed as follows. The rice plant biomass, N accumulation, NUE and number of adventitious roots per plant for ZH were all superior to HS. Furthermore, aerenchyma development (expressed as POR) of ZH was also much better than that of HS. The ammonium (NH+4) concentrations in rhizosphere and bulk soil for ZH were much lower than those for HS, but the reverse was true for nitrate (NO-3). The mineral N (NH+4 and NO-3) concentrations in root surface soil were not significantly different between ZH and HS. Interestingly, the maximal nitrification activities were always found at the distance of 2 mm away from the root surface, and they were 0.48 and 0.31 μmol kg-1h-1 for ZH and HS, respectively. The nitrification activity decreased with the increasing distance from the root surface, and it was almost the same at the zone of 10-20 mm away from the root surface as the bulk soil. The rhizosphere nitrification activities for ZH were always much higher than HS, while there had no statistically significant difference of nitrification activity in root surface and bulk soil between both rice cultivars. Compared with the CK (rice plant free), the rhizosphere nitrification activities increased for 2-3.5 times. Although rhizosphere nitrification happened in red paddy soil was very weak, it might be important for rice growth and N nutrition at the seedling stage.