Abstract: Plot experiments were carried out in the field to determine the variation in the contents of dissolved organic carbon (DOC) , microbial biomass carbon (MBC) , readily oxidizable carbon (ROC) and particulate organic carbon (POC) in the rhizosphere soils on which different varieties of rice were planted.The results showed that the DOC, MBC, ROC and POC contents in the soil when the regular indica rice was planted ranged 68.36-97.85mg·kg-1, 292.00-434.24mg·kg-1, 4.32-6.72g·kg-1 and 21.55-32.28g·kg-1, respectively;and, when the hybrid indica rice was planted, they were 80.06-98.28mg·kg-1, 362.62-521.64mg·kg-1, 4.71-6.82g·kg-1 and 25.59-34.81g·kg-1, respectively.It appeared that, aside from the possible environmental factors, variety of the rice planted on the soil played a critical role on those differences.The underlying mechanism, which might relate to the carbon input/output as well as the carbon distribution and bio-carbon utilization of the soil-crop system, would be, therefore, of great interest to be studied.