Abstract: The morphological and physiological indexes and the mineral element contents in different organs of 4 genotypes of sesame were examined under controlled oxygen supply. The number of adventitious roots of flooding tolerant varieties, Wild No.7 and Yuzhi No. 1, increased 4～5 fold, the activity of ADHenhanced about twice, but the net photosynthetic rate (Pn) decreased slightly. There were significant increase in Ca and Pand little decrease in Kin roots, and decrease in other elements in roots and 8 elements in stems and leaves. As for less flooding-tolerant genotypes, Danbackaggce and Suiping Xiaozhihuang, however, the number of adventitious roots increased little, the activity of ADHenhanced 5～9 folds, and Pn decreased by 50～60%. An increase in Ca and P, and a significant reduction in Kwas found in roots. It was concluded that the waterlogging tolerance of sesame depended firstly on the structural adaptation, then on the anoxia metabolism, and that Ca and Pmay play an important role in the metabolic adaptation to the anaerobic environment for plant survival.