This paper focuses on the analysis of the effects of groundwater tablecontrol under different irrigation water amounts on the water and salinity balance and on cropyield. Two experimental areas, the Pingluo and Huinong experimental sites, were selected to collectthe required data. The agro-hydrological model Soil-Water-Atmosphere-Plant (SWAP) was used toanalyse the water flows and salt transport processes for different groundwater levels and irrigationscenarios. Six scenarios, which resulted from different groundwater table regimes combined withdifferent irrigation amounts, were simulated. The results show that high ground-water tables due tothe excessive irrigation are the main cause of the large amount of drainage water and low cropyield; reducing irrigation water without a lower groundwater table will not lead to a largereduction of the drainage water, and will reduce the crop yield even more; to lower the groundwatertable is a good measure to control the drainage water and increase crop yield.