On the basis of NDVI and wind data recorded at meteorological stations in northwestern China, the effect of vegetation cover on wind-sand activity and its regional difference were discussed. The results show that vegetation cover is one of the most important inhibiting factors for wind-sand activities. There is close relation between positive NDVI anomaly and negative wind-sand index anomaly. The Kendall correlation coefficient between NDVI and frequency of sand-blowing days, dust storm days and strong wind days is -0.437(99% confidence level), -0.338(95% confidence level), and -0.251(90% confidence level), respectively. The correlation between NDVI and wind-sand activity index varies with different seasons and with terrains. The correlation is most significant in hill-lowland-valley.