Abstract: Beta diversity is an important component of biological diversity and plays a crucial role in the detecting of biodiversity. Based on the direct and indirect measure of ecological similarity, phylogenetic and functional beta diversity can provide new insights into assembly mechanisms of community ecology. To reveal the underlying ecological processes, we measured 4 functional traits of 45 woody species (maximum plant height, leaf area, specific leaf area, and leaf nitrogen contents) in a well-mapped 40 ha broadleaved Korean pine mixed forest plot in Changbai Mountains, Northeast China. Next, we calculated the functional and phylogenetic beta diversity through the Srensen index and compared observed pattern with null model approach to test for non-random functional and phylogenetic beta diversity at different spatial scales (radius 10, 20, 25, 50, and 75 m). Our results showed that: 1) the phylogenetic and functional similarity decreased with distances and increased with grain sizes. 2) All the phylogenetic and functional beta diversity showed non-random pattern. As the increase of grain size, the phylogenetic beta diversity showed random only in the 25-50 m scale, while lower than random in the scales of 10-20 m and 75 m. The functional beta diversity turned from random (10-50 m) to lower than random (75 m). The results suggest that in the middle and small scales (10-50 m), neutral process is more important, but we cannot rule out the role of niche process, and with the increase of scale, habitat filtering determines the community assembly in the broadleaved Korean pine forest. 3) The mismatch between functional and phylogenetic beta diversity patterns could be partly explained by the lack of phylogenetic signal for most traits.