Abstract: A horizontal division of root system was used to study the utilization ability of insoluble phosphate in low-phosphorus-tolerant cultivars(Ltz3) and l ow-phosphorus-sensitive cultivars(Xsbl). The results were as follows: Compare d to treatment with normal level phosphorus of solution in the lower pot, the dry matter weight, root oxidation decreased, MDA content increased in the treatment without phosphorus in whole system, but in the treatment with insoluble phosphat e in quartz in upper pot, the indexes changed more slightly and had higher phosp horus content, which suggested the active mobilization of phosphate of root had functioned; Low-phosphorus-tolerant cultivar had higher dry matter weight, roo t oxidation, phosphorus content and lower MDA content than low-phosphorus-sensit iv e cultivar, indicating its utilization ability of insoluble phosphate was strong er. The differences of each index among treatments with different insoluble phos phate might be related to the different availability of different insoluble phos phate on rice. The ratio of root to shoot increased under low phosphorus or phos phorus deficiency condition, and the lower phosphate availability, the ratio of root to shoot was higher.