In order to explore the characteristics of soil moisture avilability for plant recruitments of the two dominant species Agropyron mongolicum and Caragana korshinskii in desert grassland-shrubland transition of eastern Ningxia, the soil moisture thresholds of the two plant species were caculated by conducting field observations and drought stress experiments based on the previous study on the soil water potential threshold for germination. The results showed that soil moisture in the depth of 0-200 cm soil has been decreasing during the transition from desert grassland to shrubland over the past 30 years, and the soil water content of shrubland was significantly lower than that of desert grassland by 52.43% (P<0.05), that is, shrub introduction had accelerated the process of soil drought. With the process of the seedling establishment of Caragana korshinskii and Agropyron mongolica, the chlorophyll content firstly increased and then decreased with the drought stress increase, meanwhile the mortality rate gradually increased. The fitting function of osmotic potential and mortality and soil water characteristic curves of the transitional sites were used to determine the soil water potential and soil moisture thresholds for seedling establishment of the two plant species. The results showed that the soil water thresholds of Caragana korshinskii were all lower than those of Agropyron mongolica in each transition site, and the average soil water potential thresholds of the two species were -9.38--9.95 kPa, -8.72--9.28 kPa, and the average soil moisture thresholds were 4.93%-5.23%, 5.92%-6.50%, respectively. In summary, compared with soil water acquirement of Agropyron mongolica, Caragana korshinskii is more adapted to soil drought caused by shrub introduction and climate change to recruit more successfully.