Horizontal spatial variations of nitrification-denitrification in soil and its ecological factors in the soil of rice rhizosphere were determined by the eco-modeling technique and cutting method.Results indicated that the potential nitrification and denitrification intensities in soils decreased with increase in distance from the rice root interface.The potential nitrification intensity in soil dropped down sharply with increase in distance, but the potential denitri6cation intensity changed moderately, because the nitrifying bacteria are strict aerobic-autotrophic microorganisms and the denitrifying bacteria are facultative anaerobes.The amount of available carbon in soil and the ratio of that to the amount of available nitrogen reduced with increase in distance from the root interface, but the amount of available nitrogen increased.The amount of nitrosofying bacteria was larger in the zones of 10-20mm and 20-30mm from the root interface than that of 0-10mm due to the competitive absorption of nitrogen.