Abstract: In order to investigate the genotypic variation of maize in uptake and utilization of sparingly soluble phosphate under Low-P stress, two inbred lines SDKH502 and SDLH502 of maize with different phosphorous use efficiency are used as materials. Sand pot and hydroponics experiments are carried out to study the effect of differences phosphorous supplying on growth of seedling, and the ability of mobilization and utilization for sparingly soluble phosphate (Al-P, Ca-P or Fe-P) of maize. The experimental results demonstrate that the root exudates can mobilize the sparingly soluble phosphates in the condition of normal phosphate supply and phosphate starvation, and phosphate starvation caused the improvement in mobilization of sparingly soluble phosphate (Al-P, Ca-P or Fe-P). Compared with normal phosphate supply condition, the ability of activating the sparingly soluble Al-P, Ca-P, Fe-P by root exudates of SDKH502 increased by 69.28%, 87.34% and 51.83%, while the SDLH502 enhanced by 165.67%, 141.13, and 6.35% under phosphate deficient condition. Beside that, the organic acids secretion from roots of SDKH502 and SDLH502 increased by 26.96% and 18.85%, pH value depressed by 0.79 and 0.57 units separately. There were remarkable differences between SDKH502 and SDLH502 in responding to phosphate starvation. Those results above showed that, the difference of the secretion of organic acids and proton might result in various mobilization and absorption ability of sparingly soluble phosphate between SDKH502 and SDLH502.