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This article attempts to analyze the impacts of sampling extent and sampling spacing on soil air permeability’s spatial variability, and preliminary discuss the scale-dependency. The spatial variation of parameters in Linze County, an agricultural area in the middle reaches of Heihe River Basin, was examined. A study in a 21m ×21m of wheat zone was carried out, and the spatial variation of soil air permeability was analyzed with all the data measured under 3m×3m sampling grid. Then, re-sampling technique was employed with including coefficient of variation, correlation length and Moran’s I index were applied to each scenario to characterize the degree of spatial variability of soil air permeability. The results showed that all measured indices increased with various degrees with increasing extent. However, the spacing did not affect coefficient of variation and Moran’s I index, while correlation length decreased with the increase of the spacing.