On the basis of the equations coupling model for water/hear transfer in cropped soil,improvement is made on the water-uptake-by-root function(WURF),leading to a version that is related only to precipitation,crop development period a nd leaf area index as the affecting factors whereby a new model of soil water prediction is established.Thus,only with conventional meteorological variables,soil temperature,soil hydrological parameters and crop growth stage fed into the model,can prediction be satisfactorily performed of soil water regime in winter wheatfields, with the maximum relative error averaging within 8%.