The effective unsaturated hydraulic conductivity in stratified soils is evaluated using a three-dimensional stochastic approach. Because of the disparity of the correlation scales in a stratified soil, the general stochastic equations are simplified. This allows analytical evaluation of generic expressions for the effective hydraulic conductivities. Simple asymptotic expressions, valid at particular ranges(wetting front, drying condition, wetting condition) of the mean flow characteristics, are also derived. An example of applying the derived theoretical result to a imaginaryl clay soil is presented. It reveals found that the effective unsaturated hydraulic conductivity showed large-scale hysteresis. Such large-scale hysteresis was produced by the spatial variability of hydraulic soil properties rather than hysteresis of the local parameters. In addition the results show that the effective hydraulic conductivities were larger in the case of accommodating heterogeneity of soil preperties rather than neglecting heterogeneity of soil properties.