Abstract: he hydraulic properties of three unsaturated purple soils were determined by a simple horizontal infiltration method in one-dimensional horizontal infiltration experiment. While the study accurately estimates soil water retention curve, its estimates of soil water diffusion and conductivity are not very accurate. Estimated soil water diffusion and conductivity of the three purple soils by the simple infiltration method are 1~2 order of magnitude lower than that of the measured values. However, the model-estimated and measured variation tendencies of soil water diffusion and conductivity are similar. Under high soil water conditions, the estimated soil water diffusion and conductivity by the horizontal infiltration method are lower than that of the measured values. However, under low soil water conditions, the estimated soil water diffusion and conductivity by the horizontal infiltration method are higher than that of the measured values. This suggests that the model slowly responds to soil water change.