To clarify the response of soil moisture to extreme drought precipitation in typical plant communities in the desert steppe. In this study, the soil water content of four typical plant communities (Agropyron mongolicum, Sophora alopecuroides, Stipa breviflora, and Achnatherum splendens) in this region is studied. The 0—120 cm soil water content of these communities was monitored from 2020 to 2021, respectively, to analyze the dynamic characteristics of soil water content and its response to precipitation during the consumption, recovery, and stabilization periods. The results showed that during the soil water consumption period, the soil water maintained a deficit state of 4.56%~7.87%, and this state extended from 0—40 cm shallow soil layers to 80—120 cm deep soil layers with the continuous drought. During the soil moisture recovery period, the concentrated Ⅴ grade precipitation (single ＞20 mm) could restore the soil moisture in the depth of 80—120 cm, and the soil moisture was mainly recovered in the shallow layers of 0—40 cm with the continuous drought. During the soil moisture stabilization period, the soil water content in each layer of the four plant communities was ＞10% as the drought continued. By comprehensive comparison of the four plant communities, the soil water content of Stipa breviflora community was relatively high in each period, and the soil water recovery of this community was synchronized in the shallow layers and deep layers, which has important reference value for vegetation restoration and conservation in the water-restricted areas.