Alpine ecosystem of source region of Yarlung Zangbo plays a vital role in maintaining ecological security of its middle and lower reaches with great population. The eco-environmental quality deteriorated evidently in recent years. The present paper explored spectral characteristics of grassland features, plant community and the corresponding spectral pattern of vegetation succession during the process of degradation. The result showed that the difference in spectral features of Kobresia littledalei, Stipa purpurea, Kobresia pygmaea and Potentilla fruticosa, as main vegetation types of alpine meadow, alpine steppe and brushwood, mainly occurred in the position and shape of red edge, chlorophyll absorption feature and cellulose absorption features. During the process of degradation, reflectance values decreased gradually and spectral features of soil background appeared with deterioration of chlorophyll absorption and water absorption features. Vegetation indices capturing features of Chlorophyll absorption and red edge can be used to monitor grassland degradation.