With NOAA-AVHRR dataset，NDVI (Normalized Difference Vegetation Index) as index of vegetation cover feature, this paper analyzed the spatial distribution and temporal variation of vegetation cover over Tibet area. It investigated the vegetation status during different seasons, along with the relation between meteorological factors and vegetation cover with different vegetation type. These studies are based on the correlation coefficient between precipitation at different periods and maximum NDVI, NDVI in typical area and precipitation, temperature.