Abstract: The paper described the physical course of soil water infiltration under bed-irrigating sowing. Two-dimensional mathematical model was developed to simulate soil water infiltration. The model was solved numerically by an approach of the ADI difference procedure. The numerical results were compared with results of indoor test. It indicated that the method was reliable. And the numerical results were analyzed. The analysis showed effects of soil-returning volume, lower initial soil moisture content and width of seed ditch on the infiltration. And three conditions of favorable soil-returning volume was suggested.