Radial hydraulic conductivity of root is usually measured using potometer method and both root xylem water potential and the conductivity can be measured by solutions with different osmotic potentials. In this paper an improved method was presented to measure axial changes in root xylem water potential and radial hydraulic conduct ivity of corn at different distances from root apex. The results indicated that root xylem water potential decreased continuously along 9 cm from root apex. Soil drought not only decreased root xylem water potential but also increased the decreasing degree of root water potential along 7 cm from the root apex. The apical zone was the most sensitive zone to water stress. Root radial hydraulic conductivity gradually increased within the first 3 cm from root apex, reached maximum and maintained constant between 3 cm and 10 cm and decreased thereafter. Water stress decreased radial hydraulic conductivity earlier and made the gradient of its axial changes smaller.