We re-built MODIS-NDVI data based on the asymmetric gauss function (AG) of Timesat, by using a dimidiate pixel model to estimate the vegetation coverage (VC) of the Loess Plateau over the past decade. The model analyzed the annual temporal variation of VC in relation to precipitation and temperature. Results showed that the VC of the Loess Plateau decreased from the southeast to the northwest. Average VC was highest in the forest ecosystem, followed by the shrub and grassland ecosystems; it was lowest in the desert ecosystem, which showed significant spatial variation. In 2010,the VC in forest ecosystems was 81.6%,mainly including the Taihang and Luliang Mountains and the Qinling area. Forest ecosystems in the warm-temperature region are predominantly covered by broadleaved deciduous trees, which present high coverage up to above 80%all year round. The VC in the northwest temperate grass zone reached 38.8%. Typical steppe ecosystems are mainly covered by xeromorphic perennial herbs distributed on the temperate grassland in a southeast-northwest direction according to the moisture gradient, and the VC presented a similar declining trend. The annual VC increased on the Loess Plateau (78.6%), whereas it decreased (19.4%). VC increased in spatial distribution from Yulin to Yan'an but declined from Lanzhou to Yinchuan where it was concentrated in relatively small patches. Variations in precipitation and temperature were correlated to each type of VC. We found that the change in VC is affected by climate change and human activities. In the sparsely populated northwest Loess Plateau,vegetation growth is mainly influenced by natural factors and less by human activities; however, in the densely populated southeast, vegetation growth is affected more by human factors, including socioeconomic and technological factors, than by natural elements.