Abstract: The correlation between Al-tolerance and root activity were studied with inbred lines and part of their F1 generations in maize, by the means of nutritional cultivation. The results indicated that, under Al stress, root reducing ability of Al-tolerant inbred lines was enhanced while TTC reducing ability decreased in Al-sensitive ones, which shows TTC reducing ability of root is closely consistent with the ability of Al-tolerance. The active absorption area in Al-tolerant inbred lines is much larger that of Al-sensitive ones, what’s more, the active absorption area to the total absorption area ratio is even higher compared with the Al-sensitive ones. The oxidbillity of root in Al-tolerant inbred lines could be maintained or slightly increased by aluminum stress while that of sensitive ones decreased. The results suggest that Al-tolerant inbred lines can keep high respiration metabolism when they stressed by Aluminum. The bleeding sap could be decreased in both inbred lines especially Al-sensitive lines when treated with Al.