Caragana species are able to survive in the stressful climatic conditions (e.g. very limited precipitation, high temperature and strong solar radiation) within the desert region on the Inner Mongolian Plateau through ecological adaptations to the environment. In the desert region, precipitation has the most important influence on plant growth and development. In order to understand how Caragana species are adapted to the arid desert environment, we investigated daily and seasonal variation in the hydraulic architecture (specific conductivity, leaf specific conductivity and Huber value) of four dominant Caragana species (Caragana korshinskii, C. stenophylla, C. tibetica and C. roborovsky), which grow in the desert region on the Inner Mongolian Plateau. We examined the hydraulic architecture of these Caragana species using the improved flushing method. The results showed that there was significant daily and seasonal variation in the hydraulic architecture of the four Caragana species. For all four Caragana species, the specific conductivity and leaf specific conductivity were high in the morning and afternoon and low at noon, showing a curve with single valley. Specific conductivity and leaf specific conductivity were highest in the summer, while Huber values were highest in spring, lower in summer, and lowest in autumn. There was also significant interspecific variation in hydraulic architecture among the four Caragana species. For daily averages of specific conductivity in the three seasons, leaf specific conductivity in summer and autumn, and Huber value in the three seasons, our results followed the pattern : C. korshinski > C. roborovoskyi > C. tibetica > C. stenophylla. For diurnal variation extent of specific conductivity in the three seasons, and leaf specific conductivity in the spring, our results followed the pattern: C. korshinski > C. roborovoskyi > C. stenophylla > C. tibetica. Seasonal variation extent of the daily average of specific conductivity was similar among the four Caragana species. Based on our results, we drew the following conclusions: (1) The hydraulic architecture of the four desert Caragana species limited water transport, which might decrease transpiration at noon. (2) Caragana species might be adapted to high temperatures and strong solar radiation through high water transport efficiency and better water supply to leaves to maintain relatively stable water status. The seasonal variation in Huber values ensured better water supplies to the four Caragana species in the spring and summer, when these species grew relatively rapidly. (3) Among the four Caragana species, C. korshinskii had the highest specific conductivity, leaf specific conductivity and Huber values, resulting in better water supply and higher transpiration rates, and thereby faster growth rates, which suggests that C. korshinskii is better adapted to the desert environment than the other three Caragana species. However, although C. korshinskii had higher water transpiration efficiency, this species was more prone to having serious cavitation and embolism.