Analyzing spatial patterns of species can provide many important clues about the underlying processes that have generated these patterns. Natural secondary prince rupprecht′s larch forest, spruce forest and poplar-birch forest in Guandi Mountain are representative forest types of high altitude area in Northern China. In this study, the three typical natural secondary mountain forest plots narrated above were established to analyze and compare spatial patterns of dominant tree species populations. In the plots, all arbor species at least 1cm diameter at breast height (DBH, 1.3m above ground) were mapped and identified to species, and their geographic coordinates were recorded following a standard field protocol. The pair correlation function, univariate O-ring statistic of the point pattern analysis, was used to analyze spatial distribution of tree species in each community, while bivariate O-ring statistic was used to analyze spatial associations of different species in each community. The change of population spatial pattern and association for same species among different forest communities was compared to explore inherent formation mechanism of spatial patterns. We found that: (1) Most populations in three communities showed significantly aggregated distributions at relatively smaller scales and random distributions at larger scales, and the degree of aggregation decreased with increasing spatial scales (2) There are large differences among the spatial patterns of the same species in different forest communities. Betula albo-sinensis, B. platyphylla and Populus davidiana were significantly aggregated at smaller scales in deciduous forests, but randomly distributed in conifer-dominated forests. For Larix principis-rupprechtii, The young trees were aggregated in mixed broadleaved secondary forest, while the old ones were regularly distributed at small scales and randomly distributed at large scales in Larix principis-rupprechtii-dominated conifer forests. (3) Spatial associations among tree species in the three communities were mainly found at smaller scales and gradually disappeared with increasing scales. In broadleaved species dominated secondary forest, there were significantly positive associations among the young Larix principis-rupprechtii and Betula species. However, in Larix principis-rupprechtii-dominated conifer forest, there was no significant association among them. In summary, spatial pattern and associations of tree species in the three communities varied greatly with tree age, size and community structure. This study result aims at providing a theory basis for going deep into a cognition for the formation of spatial patterns, the maintenance mechanisms and dynamics of the populations, knowing further about biodiversity and species coexistence mechanisms of mountain secondary forest communities of Northern China.