Abstract: Understanding soil water dynamics is crucial to water resource management and ecological construction in oasis regions. In this paper, a case study was conducted to examine the spatial-temporal distribution characteristics of soil water using geostatistical analysis and temporal stability analysis in the oasis-desert ecotone of the middle reaches of Heihe River Basin, based on the field monitoring of soil water content throughout the growing season from 2012 to 2014 in a 50 km² area. Results showed that soil water storage for the oasis-desert ecotone on the north shore of the Heihe River was highest in August and lowest in October. The mean soil water storage in the 0-2 m profile was approximately 367 mm. The gradient distribution of soil water storage from the oasis to the desert was not only related to the river channel but also to the land use type. Soil water storage in different land uses followed the order of cropland>forest land>shrub land>desert. On average, soil water storage in the cropland was300% higher than that in the desert. There existed great differences in the temporal stability of soil water storage at different sampling points, and the strength of temporal stability in various land uses was in order of shrub land>desert>cropland>forest land. The seasonal variations of river water had direct effects on soil water within the distance of 3 km. A time-stable transect of soil water was observed between the river-bank oasis and the newly cultivated cropland, which indicated the development and evolution of the oasis ecosystem.