Qiliyu region is located between the eastern margin of the Lingkong mountain and northern margin of the Mianshan Mountain, and it shows distinct transitional vegetation types and high species richness. The phylogenetic structure of a community is composed of the genetic relationships between species across the community. Phylogenetic structure is a synthetical indicator reflecting community construction’s three ecological processes which are habitat filtering, competitive exclusion and stochastic processes. Understanding of the phylogenetic structure of a community will provide new insights into the different ecological processes in constructing the community. Our objective was to examine the effect of spatial factor on phylogenetic structure and determine the relative importance of neutral theory and niche theory in building the plant community in Huoshan mountain. We compared the phylogenetic structure of the community along different altitude gradient using data from 1 200 to 2 000 m, and examined the effects of five spatial scales(100, 400, 900, 1 600 and 2 500 m²) and six DBH classes(Ⅰ. DBH<5 cm,Ⅱ. 5 cm≤DBH<10 cm,Ⅲ. 10 cm≤DBH<15 cm,Ⅳ. 15 cm≤DBH<20 cm,Ⅴ. 20 cm≤DBH<25 cm,Ⅵ. DBH≥25 cm) at five spatial scales on phylogenetic structure of the community in Qiliyu region. The results demonstrated that: (1) there were certain phylogenetic structure at all different altitudinal gradient. The phylogenetic structure of community was dispersed at middlelow altitude and clustered at higher altitude. (2) Communities were phylogenetically clustered at all spatial scales. With increasing spatial scale, the phylogenetic structure tended to cluster. (3) The effects of six DBH classes at five spatial scales on phylogenetic structure of the community were examined, which shows the result that the degree of phylogenetic clustering decreased with increasing DBH classes. However, the degree of phylogenetic clustering at the scale of DBH Ⅵ was higher than the Ⅳ and Ⅴ. It turns out from our research that the prediction of niche theory is more important than the prediction of neutral theory in building the plant community in Huoshan Mountain of Shanxi.