Quantitative identification of water utilization characteristics of xerophytic shrubs is an important prerequisite for the selection and optimization of a regional artificial sand-fixing vegetation system. In this study, a hydrogen (δD) stable isotope technique was used to study the changes in water use characteristics of four typical xerophytic shrubs,Caragana korshinskii,Salix psammophila,Artemisia ordosica, andSabina vulgarisin the Hobq Desert under light (4.8 mm after 1 and 5 days) and heavy (22.4 mm after 1 and 8 days) rainfall events. Under light rainfall,C. korshinskiiandS. psammophilaprimarily used the 80–140 cm layer of soil water (37–70%) and groundwater (13–29%), and the water use characteristics did not change significantly after the light rainfall event. However, the utilization ratio ofA. ordosicato soil water in the 0–40 cm layer increased from less than 10% on the first day after rain to more than 97% on the fifth day after rain, whereas the utilization ratio ofS. vulgaristo soil water in the 0–40 cm layer also increased from 43% to nearly 60%. Under heavy rainfall,C. korshinskiiandS. psammophilastill used the 60–140 cm layer (56–99%) and groundwater (~15%), while the main water utilization depth ofA. ordosicaandS. vulgarisexpanded to 0–100 cm. Based on the above results,C. korshinskiiandS. psammophilaprimarily use the soil moisture of the 80–140 cm layer and groundwater, whileA. ordosicaandS. vulgarisuse the soil moisture of the 0–100 cm layer. Therefore, the co-existence ofA. ordosicaandS. vulgariswill increase the competition between artificial sand-fixing plants, while the combination of the two plants withC. korshinskiiandS. psammophilawill avoid competition between artificial sand-fixing plants to some extent. This study provides important guidance for regional vegetation construction and sustainable management of an artificial vegetation system.