Abstract: The effects of different size shrub (two groups of Reaumuria soongorica shrubs) on the spatiotemporal heterogeneity of soil properties were studied in the eastern Alxa Plateau. The soil organic carbon (SOC) and total nitrogen (TN) were significantly higher in the nebkha (dune) beneath and at the perimeter of shrub canopies. No differences were observed for SOC and TN in nebkhas under shrubs of different size. However, soil water content of nebkhas increased markedly with increasing shrub size. Soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were 55.23-113.81 mg/kg and 5.46-7.66 mg/kg, respectively. The soil MBC and microbial quotient (qMB) were significantly higher beneath the shrub canopies than at the perimeter. The soil microbial biomass and activity beneath the shrub canopy remained relatively stable. The nebkha under the shrub canopies contained more nutrients but was not affected by shrub size. The formation of nebkha played an important role in maintaining the stability and health of the soil microenvironment beneath shrub canopies.