Research on sand flux is an important component of blown sand physics and engineering. In the present study, the researchers used GIS-based spatial analysis to calculate the distribution of sand flux above the surface of a barchan dune and to develop a sand flux model. The researchers  sampled the diameters of sand grains and wind velocity above the surface of a barchan dune in the Taklimakan Desert, then observed sand flux at five positions above the dune. Data of sand grain diameters and wind velocity were interpolated by means of the Kriging and the Inverse Distance Weighting methods, respectively. The analysis produced graphs of the distribution of sand grain diameters and wind velocity above the barchan dune. The sand fluxes at five positions were calculated by means of the three common sand flux models, and the results were compared with the observed values. The S rensen sand flux model has an optimal fitting, it was used to integrate the data on sand grain diameters and wind velocity so as to compute sand flux above the surface of the barchan dune. Based on this analysis, the researchers obtained the total sand flux above the surface of the barchan dune. This approach has overcome some deficiencies of traditional fixed position observation method.