Aiming to determine the soil water-groundwater dynamics and their transformation relationship in the Hetao Irrigation District under the background of restricted water diversion, so as to provide a theoretical basis for optimizing farmland water management strategies, a typical bucket canal area in Hetao Irrigation District was selected, and the dynamic changes of farmland soil water in different crop planting areas and groundwater in different irrigation periods were analyzed based on the monitoring data of soil water and groundwater in two years. Using soil water balance to quantitatively study the transformation relationship between farmland soil water and groundwater in shallow groundwater areas, the results showed that the change of farmland soil moisture during the growth period belonged to the “irrigation precipitation infiltration supplement-evapotranspiration type”; it was different due to irrigation. The dynamics of groundwater depth during the period had significant characteristics, and the groundwater depth fluctuated drastically with the leakage of soil moisture in the farmland; during the growth period of crops, soil water and groundwater were recharged in both directions, and different periods had different transformation characteristics; the internal irrigation and precipitation replenish soil water were 544.56mm and 541.85mm in 2a growth periods, respectively. The average evapotranspiration in the study area was 465.5mm and 434.8mm, respectively, the soil water storage was reduced by 61.96mm and 63.1mm, respectively, and the soil water replenishing groundwater was 207.73mm and 236.94mm, respectively. The research results can provide a scientific basis for agricultural water-saving irrigation in the local and similar areas.