This study is designed to elucidate the impact of interannual variability of meteorological parameters to vegetation activity over Mongolia using 10-day composite AVHRR NDVI data and surface meteorological data (precipitation, temperature and snow depth) for 97 meteorological stations from 1993 to 2000. The analysis is made on vegetation in two developmental stages; the rapid-growth stage and the mature stage. Positive correlations at 99% significant level between precipitation and vegetation activity are recognized for 29 % and 42 % of meteorological stations in the rapid-growth stage and the mature stage, respectively. Precipitation in June and July impacts vegetation activity in both stages. The impact of air temperature to vegetation activity differs by season. Mature stage vegetation activity is negatively correlated with summer temperature over most area. In the rapid growth stage, negative correlations are found over the western part of Mongolia with respect to temperature in early winter, and positive correlations are concentrated in the northeastern part of Mongolia with respect to temperature in midwinter. There are five meteorological stations near the Henty Mountains with high correlation coefficients between snow depth and vegetation activity in the rapid-growth stage; however, the snow depth effect is limited to a narrow region. The possibility of prediction the vegetation activity in the two stages is examined using a multiple regression method based on the above-mentioned results. The prediction algorithm is valid for more than half of stations over Mongolia.