10 sample plots were set along a gradient of aridity in the alpine meadow, the Dongda Mountain in Southeastern Tibet. Species Kobresia pygmaea and K. humilis were selected as the study materials, and liner regression analysis was used to analyze the correlation between the amount of leaf and numerical value of other components of plants, such as amount of ramet, diameter of base stem, amount of root and length of root. The slopes of liner regressions were used to measure the effect of tillering, germination ability of leaf, effect of root branching and root elongating. The results showed: (1) leaf amount and numerical value of other components of the two Kobresia plants were significantly positive liner correlated (P< 0.01). (2) With aggravation of aridification, ramet amount of K. pygmaea increased, while that of K. humilis decreased. For two plants, the tillering effect decreased, which indicated that leaf amount of per ramet reduced due to the aridification. (3) Diameter of base stem and germination ability of two plants decreased with aggravation of aridification. Germination ability of K. pygmaea was in correspondence with drought gradient; there was no regular variation of germination ability of K. humilis along the gradient of aridification, but it decreased to an extreme value when habitats presented to be very dry. (4) For plant K. pygmaea, its amount and length of root both increased; for plant K. humilis, its root length increased, but root amount showed irregular variation; the effect of root branching and root elongating both decreased along the gradient of aridification. In summary, this study showed that the most suitable habitat for Kobresia plants was marsh land with shallow water. K. pygmaea can better adapt to aridification and distributes at a wide range by lowering germination rate of leaf for decreasing transpiration, increasing ramet amount for increasing the spatial occupation ability, and increasing root amount and length to enhance the ability to absorb soil water, while K. humilis responses to aridification only by lowering germination rate of leaf and increasing root length, which shows a weak adaptation to arid habitat and distributes at a narrower range.