The transport and regime of water and salt under crops are a very complex physical chemical biological system.The study of their laws and characteristics is very important to developing water and salt transport models, guiding of sustainable exploitation of salt-affected soils and irrigation management, explaining interaction between sustainable agriculture and environment, and forecasting water and salt transport.Therefore, a soil water and salt transport model (SWSTM) was developed and adopted to describe transport of water and salt under winter wheat crop, numerical simulation of water and salt regime was done, and water and salt transport under different climate conditions and groundwater conditions was predicted and forecast with the SWSTM model.The results show that the simulation is very ideal and it is practicable to do numerical simulation and forecast with this model.So, a new method to forecast water-salt regime is thus brought forth.Furthermore, according to the actually situation, a simplified useful method without complex calculation is expected to be applied to forecasting distribution of salt-affected soil resources and water and salt regime on a large scale.