Abstract: Considering soil plant atmosphere as a continuum,sopping potential,ability of consume water and efficiency of water using for different species were studied,and the tolerate drought adaptability of species groups of adaptation grade in Karst forest was evaluated.The results showed that there were different water balance ways for different species groups.Pioneer species with high input and low output belong to high efficiency type;Sub pioneer species with middle input and output belong to higher efficiency type;Transition species with lower input and middle output belong to lower efficiency type;Sub climax and climax with middle input and output belong to efficiency.The adaptability of tolerate drought for pioneer and sub pioneer species were higher than of sub climax and climax species.The adaptability of tolerate drought of deciduous broad leaved trees was lower than of evergreen broad leaved tree.The judgment that deciduous broad leaved tree in Karst forest adapted in dry habitat was proofed.