The mechanism of water and salt movement in the soil is analyzed by modelling, and general ways of thinking of the setup of a convection-dispersion equation and limitations of the numerical value method are summarized. From the angle of the 3S (GIS, RS and GPS) technology, the research on spatial modelling of the soil water and salt movement is generalized, and the issue of integration of the solute mobilization model and GIS explored. At the same time it is pointed out that development of the techniques of GEODATABASE and COM provides a chance for development of the integration of GIS with the modeling of the mechanism of soil water and salt movement.