Abstract: In this paper, based on the experimental data of maize, sunflower, acacia confusa and leucaena glauca under various treatments of temperature and soil water potential , the effects of temperature and soil water potential on root shrinkage and the hydraulic conductivity in the gap of soilroot interface as well as the relative importance of hydraulic conductivities in soilroot system　were analysed.　The results indicated that root shrinkage has apparent difference for different four kind plants in experiment, i. e.， maize >sunflower>acacia confusa > leucaena glauca, the root shrinkage state under water stress reflect the droughtresistance of plant. At same soil water potential, the conductivity in the gap of soilroot interface is that leucaena glauca>acacia confusa > sunflower >maize. Among the gap conductivity (L_ｇ)，root system conductivity (L_r)　and soil effective conductivity (L_s), the change range of L_s is largest, and that of L_r is smallest. Wether one of L_r, L_ｇ and L_s　is the factor limited water transport in soilroot system or not, is determined by soil water potential range, when soil water potential (ψ) is larger than -1.0 MPa, tempeature increase or decrease has not apparent effect on root shrinkage for maize and sunflower, when ψ is lower than -1.0MPa, the root shrinkage is increased as temperature increases.