Abstract: Method of community ecology was used in the analysis of subalpine shrub-meadow communities in the semiarid Lhasa Valley to effectively prevent the degeneration of mountainous vegetation.The results showed that there were 67 species of vascular plants in 48 genera and 27 families in the shrub-meadow communities.The analysis of geographical factors and plant families and genera demonstrated that the shrub-meadow communities were temperate clearly.The analysis of both life form and leaf characteristics revealed that the physiognomy of the shrub-meadow communities was mainly affected by the nanophanerophytes with deciduous,simple and entire leaves.The subalpine shrub-meadow communities in the semiarid Lhasa Valley were characterized by the hemicryptophytes,nanophyll,herbaceous,simple leaves and entire leaves; and these communities could grow in the high and frigid mountainous regions in the arid Tibetan Plateau.Based on the characteristics of the shrub-meadow communities,the ecological regeneration was also discussed.

Key words: vascular plant, geographical factor, life form, leaf property, Lhasa Valley, Tibet