Abstract: Soil samples were collected from ten different-altitude sites along the QinghaiTibet railway, and the community DNA was extracted from the soil samples directly. Bacterial 16S rRNA gene fragment was amplified by nested PCR from the community DNA. Soil bacterial population diversity was analyzed by 16S rDNA-PCR-DGGE. The results showed that the bacterial population diversity was abundant in this high altitude area. Vegetation type was an important factor influencing the bacterial diversity and population similarity in this area, and the altitude acted as a minor impact factor. The bacterial population diversity of soil samples with similar vegetation type decreased with the increasing altitude.

Key words: Forest, Ecological environment, Jinggang Mountain forest region