Abstract: Salt accumulation under drip irrigation is a crucial problem relates to the irrigation district sustainable development directly. Mathematical simulation was an important method to answer this problem. However, the practical model was absent. We build a simplified algorithm on simulating soil water and soil salt transfer process under drip irrigation. In this model, the soil column of drip irrigation under mulch was divided into grids which used to simulated soil water and soil salt transfer process, the other hydrological process in the condition of drip irrigation under mulch, such as infiltration of precipitation or irrigation, and reallocation of soil water in unsaturated area, plant transpiration and soil evaporation also be simulated. The model was calibrated and validated by the observed data of the amount distribution and dynamics progress of soil salt obtained from field experiment which conducted in Water-saving Irrigation Experiment Station of the Shihezi University. The results indicated that the simplified algorithm well adapts to the simulation of soil water and soil salt dynamic in drip irrigated cotton field.