The dynamic processes of aeolian erosion and deposition on flat sandy surface were analyzed based on field observation and the data of regional wind regime.By calculating the drift potential and the maximum possible quantity of sand transport,a computational model was put forward for predicting the quantity of aeolian erosion and deposition on flat sandy surface,which can make up for the deficiency that both the drift potential and the maximum possible quantity of sand transport can not reveal intuitively the strength of regional wind-blown sand activity.Comparison of tendency maps showed that field measured value,predicted value by the computational model and calculated drift potential and maximum possible quantity had the same fluctuation character.Furthermore,comparison of regression equations showed that the regression equation for prediction was significant and predicted value was more close to field measured value.The computational model can better predict the strength of regional wind-blown sand activity and provides evidence for the expansion and shrink of sandy desert.