Abstract: This article presents a new numerical method to analyze the seepage through the saturated/unsaturated soils of levees or dams. This method is based on the mathematical model established in terms of the seepage regulations of saturated and unsaturated soils and compiled by coupling the saturated zone with unsaturated zone as a whole. The model is computerized by means of finite-difference method. Under the drop down condition of the upstream water level, the calculated results compare fairly well to the test results.The distribution of the seepage lines and isopotential line (isobaric lines) is reason-able and regular.