Abstract: According to the principle of salt-water balance and the observation and experimental data about ground water，irrigation and salt regimes，making use of water-need coefficient and transpiration coefficient and introducing salt and water migr ation coefficients，this paper presents a simplified model of salt-water regimes of upper soil layer under the processing of evapotranspiration．Based on the growth function of the crop roots，a water uptake ratio coefficient of crop roots is pres ented also，so that divide the lower boundary water flow into root extraction and soil capillary water movement．Intmduced salt mod ified coefficient to evapotranspiration and feedback with the salt and water production function，evapotrans-piration and the salt-water regime model are modified ．The model is simple and suitable for the regulation and control of water and salt regimes on farmland under the processing of evapotranspiration．