Abstract:The transpiration and conductivity rate of five kinds of plants widely distributed in He-Xi area and the environmental factors were measured by LI-1600 Steady State Porometer. When light intensity was not lower than that required for stomata opening, the change before peak point of transpiration rate was ,lot related to increasing rate of leaf temperatrue, but it was related positively to leaf temperature. The transpiration rate increased with increasing of the leaf thickness and the surface area in palisaoe tissue per unit leaf area within species, but not between species. The ratio of transpiration rate of upper to lower leaf surface within species was related to the ratio of number of stomata on them but no relationship was noted in interspecies.